RISC-V: Update the doc to match ISA manual

ISA manual use funct* rather than func*[1] (e.g. funct7 rather than func7),
and I realized that may something I typo at beginning when I write the patch
for `.insn` support...:P

[1] https://github.com/riscv/riscv-isa-manual/blob/main/src/rv32.adoc#integer-register-register-operations

gas/doc/c-riscv.texi

@@ -442,11 +442,11 @@ instruction formats:
 @multitable @columnfractions .15 .40
 @item opcode7 @tab Unsigned immediate or opcode name for 7-bits opcode.
 @item opcode2 @tab Unsigned immediate or opcode name for 2-bits opcode.
-@item func7 @tab Unsigned immediate for 7-bits function code.
-@item func6 @tab Unsigned immediate for 6-bits function code.
-@item func4 @tab Unsigned immediate for 4-bits function code.
-@item func3 @tab Unsigned immediate for 3-bits function code.
-@item func2 @tab Unsigned immediate for 2-bits function code.
+@item funct7 @tab Unsigned immediate for 7-bits function code.
+@item funct6 @tab Unsigned immediate for 6-bits function code.
+@item funct4 @tab Unsigned immediate for 4-bits function code.
+@item funct3 @tab Unsigned immediate for 3-bits function code.
+@item funct2 @tab Unsigned immediate for 2-bits function code.
 @item rd @tab Destination register number for operand x, can be GPR or FPR.
 @item rd' @tab Destination register number for operand x,
 only accept s0-s1, a0-a5, fs0-fs1 and fa0-fa5.
@@ -554,45 +554,45 @@ The following table lists the RISC-V instruction formats that are available
 with the @samp{.insn} pseudo directive:
 
 @table @code
-@item R type: .insn r opcode7, func3, func7, rd, rs1, rs2
+@item R type: .insn r opcode7, funct3, funct7, rd, rs1, rs2
 @verbatim
 +-------+-----+-----+-------+----+---------+
-| func7 | rs2 | rs1 | func3 | rd | opcode7 |
+| funct7 | rs2 | rs1 | funct3 | rd | opcode7 |
 +-------+-----+-----+-------+----+---------+
 31      25    20    15      12   7        0
 @end verbatim
 
-@item R type with 4 register operands: .insn r opcode7, func3, func2, rd, rs1, rs2, rs3
-@itemx R4 type: .insn r4 opcode7, func3, func2, rd, rs1, rs2, rs3
+@item R type with 4 register operands: .insn r opcode7, funct3, funct2, rd, rs1, rs2, rs3
+@itemx R4 type: .insn r4 opcode7, funct3, funct2, rd, rs1, rs2, rs3
 @verbatim
 +-----+-------+-----+-----+-------+----+---------+
-| rs3 | func2 | rs2 | rs1 | func3 | rd | opcode7 |
+| rs3 | funct2 | rs2 | rs1 | funct3 | rd | opcode7 |
 +-----+-------+-----+-----+-------+----+---------+
 31    27      25    20    15      12   7         0
 @end verbatim
 
-@item I type: .insn i opcode7, func3, rd, rs1, simm12
-@itemx I type: .insn i opcode7, func3, rd, simm12(rs1)
+@item I type: .insn i opcode7, funct3, rd, rs1, simm12
+@itemx I type: .insn i opcode7, funct3, rd, simm12(rs1)
 @verbatim
 +--------------+-----+-------+----+---------+
-| simm12[11:0] | rs1 | func3 | rd | opcode7 |
+| simm12[11:0] | rs1 | funct3 | rd | opcode7 |
 +--------------+-----+-------+----+---------+
 31             20    15      12   7         0
 @end verbatim
 
-@item S type: .insn s opcode7, func3, rs2, simm12(rs1)
+@item S type: .insn s opcode7, funct3, rs2, simm12(rs1)
 @verbatim
 +--------------+-----+-----+-------+-------------+---------+
-| simm12[11:5] | rs2 | rs1 | func3 | simm12[4:0] | opcode7 |
+| simm12[11:5] | rs2 | rs1 | funct3 | simm12[4:0] | opcode7 |
 +--------------+-----+-----+-------+-------------+---------+
 31             25    20    15      12            7         0
 @end verbatim
 
-@item B type: .insn s opcode7, func3, rs1, rs2, symbol
-@itemx SB type: .insn sb opcode7, func3, rs1, rs2, symbol
+@item B type: .insn s opcode7, funct3, rs1, rs2, symbol
+@itemx SB type: .insn sb opcode7, funct3, rs1, rs2, symbol
 @verbatim
 +-----------------+-----+-----+-------+----------------+---------+
-| simm12[12|10:5] | rs2 | rs1 | func3 | simm12[4:1|11] | opcode7 |
+| simm12[12|10:5] | rs2 | rs1 | funct3 | simm12[4:1|11] | opcode7 |
 +-----------------+-----+-----+-------+----------------+---------+
 31                25    20    15      12               7         0
 @end verbatim
@@ -614,74 +614,74 @@ with the @samp{.insn} pseudo directive:
 31           30             21           20              12   7         0
 @end verbatim
 
-@item CR type: .insn cr opcode2, func4, rd, rs2
+@item CR type: .insn cr opcode2, funct4, rd, rs2
 @verbatim
 +-------+--------+-----+---------+
-| func4 | rd/rs1 | rs2 | opcode2 |
+| funct4 | rd/rs1 | rs2 | opcode2 |
 +-------+--------+-----+---------+
 15      12       7     2        0
 @end verbatim
 
-@item CI type: .insn ci opcode2, func3, rd, simm6
+@item CI type: .insn ci opcode2, funct3, rd, simm6
 @verbatim
 +-------+----------+--------+------------+---------+
-| func3 | simm6[5] | rd/rs1 | simm6[4:0] | opcode2 |
+| funct3 | simm6[5] | rd/rs1 | simm6[4:0] | opcode2 |
 +-------+----------+--------+------------+---------+
 15      13         12       7            2         0
 @end verbatim
 
-@item CIW type: .insn ciw opcode2, func3, rd', uimm8
+@item CIW type: .insn ciw opcode2, funct3, rd', uimm8
 @verbatim
 +-------+------------+-----+---------+
-| func3 | uimm8[7:0] | rd' | opcode2 |
+| funct3 | uimm8[7:0] | rd' | opcode2 |
 +-------+-------- ---+-----+---------+
 15      13           5     2         0
 @end verbatim
 
-@item CSS type: .insn css opcode2, func3, rd, uimm6
+@item CSS type: .insn css opcode2, funct3, rd, uimm6
 @verbatim
 +-------+------------+----+---------+
-| func3 | uimm6[5:0] | rd | opcode2 |
+| funct3 | uimm6[5:0] | rd | opcode2 |
 +-------+------------+----+---------+
 15      13           7    2         0
 @end verbatim
 
-@item CL type: .insn cl opcode2, func3, rd', uimm5(rs1')
+@item CL type: .insn cl opcode2, funct3, rd', uimm5(rs1')
 @verbatim
 +-------+------------+------+------------+------+---------+
-| func3 | uimm5[4:2] | rs1' | uimm5[1:0] |  rd' | opcode2 |
+| funct3 | uimm5[4:2] | rs1' | uimm5[1:0] |  rd' | opcode2 |
 +-------+------------+------+------------+------+---------+
 15      13           10     7            5      2         0
 @end verbatim
 
-@item CS type: .insn cs opcode2, func3, rs2', uimm5(rs1')
+@item CS type: .insn cs opcode2, funct3, rs2', uimm5(rs1')
 @verbatim
 +-------+------------+------+------------+------+---------+
-| func3 | uimm5[4:2] | rs1' | uimm5[1:0] | rs2' | opcode2 |
+| funct3 | uimm5[4:2] | rs1' | uimm5[1:0] | rs2' | opcode2 |
 +-------+------------+------+------------+------+---------+
 15      13           10     7            5      2         0
 @end verbatim
 
-@item CA type: .insn ca opcode2, func6, func2, rd', rs2'
+@item CA type: .insn ca opcode2, funct6, funct2, rd', rs2'
 @verbatim
 +-- ----+----------+-------+------+---------+
-| func6 | rd'/rs1' | func2 | rs2' | opcode2 |
+| funct6 | rd'/rs1' | funct2 | rs2' | opcode2 |
 +-------+----------+-------+------+---------+
 15      10         7       5      2         0
 @end verbatim
 
-@item CB type: .insn cb opcode2, func3, rs1', symbol
+@item CB type: .insn cb opcode2, funct3, rs1', symbol
 @verbatim
 +-------+--------------+------+------------------+---------+
-| func3 | simm8[8|4:3] | rs1' | simm8[7:6|2:1|5] | opcode2 |
+| funct3 | simm8[8|4:3] | rs1' | simm8[7:6|2:1|5] | opcode2 |
 +-------+--------------+------+------------------+---------+
 15      13             10     7                  2         0
 @end verbatim
 
-@item CJ type: .insn cj opcode2, func3, symbol
+@item CJ type: .insn cj opcode2, funct3, symbol
 @verbatim
 +-------+-------------------------------+---------+
-| func3 | simm11[11|4|9:8|10|6|7|3:1|5] | opcode2 |
+| funct3 | simm11[11|4|9:8|10|6|7|3:1|5] | opcode2 |
 +-------+-------------------------------+---------+
 15      13                              2         0
 @end verbatim