gh-107298: Fix doc references to undocumented modules (#107300)

Update also Doc/tools/.nitignore.

Doc/c-api/arg.rst

@@ -477,7 +477,7 @@ API Functions
    will be set if there was a failure.
 
    This is an example of the use of this function, taken from the sources for the
-   :mod:`_weakref` helper module for weak references::
+   :mod:`!_weakref` helper module for weak references::
 
       static PyObject *
       weakref_ref(PyObject *self, PyObject *args)

Doc/c-api/codec.rst

@@ -7,7 +7,7 @@ Codec registry and support functions
 
    Register a new codec search function.
 
-   As side effect, this tries to load the :mod:`encodings` package, if not yet
+   As side effect, this tries to load the :mod:`!encodings` package, if not yet
    done, to make sure that it is always first in the list of search functions.
 
 .. c:function:: int PyCodec_Unregister(PyObject *search_function)

Doc/c-api/typeobj.rst

@@ -579,7 +579,7 @@ and :c:type:`PyType_Type` effectively act as defaults.)
    name, followed by a dot, followed by the type name; for built-in types, it
    should be just the type name.  If the module is a submodule of a package, the
    full package name is part of the full module name.  For example, a type named
-   :class:`T` defined in module :mod:`M` in subpackage :mod:`Q` in package :mod:`P`
+   :class:`T` defined in module :mod:`!M` in subpackage :mod:`!Q` in package :mod:`!P`
    should have the :c:member:`~PyTypeObject.tp_name` initializer ``"P.Q.M.T"``.
 
    For :ref:`dynamically allocated type objects <heap-types>`,

Doc/c-api/unicode.rst

@@ -1205,7 +1205,7 @@ Character Map Codecs
 
 This codec is special in that it can be used to implement many different codecs
 (and this is in fact what was done to obtain most of the standard codecs
-included in the :mod:`encodings` package). The codec uses mappings to encode and
+included in the :mod:`!encodings` package). The codec uses mappings to encode and
 decode characters.  The mapping objects provided must support the
 :meth:`__getitem__` mapping interface; dictionaries and sequences work well.
 

Doc/extending/extending.rst

@@ -367,7 +367,7 @@ Note that PyMODINIT_FUNC declares the function as ``PyObject *`` return type,
 declares any special linkage declarations required by the platform, and for C++
 declares the function as ``extern "C"``.
 
-When the Python program imports module :mod:`spam` for the first time,
+When the Python program imports module :mod:`!spam` for the first time,
 :c:func:`PyInit_spam` is called. (See below for comments about embedding Python.)
 It calls :c:func:`PyModule_Create`, which returns a module object, and
 inserts built-in function objects into the newly created module based upon the
@@ -1219,7 +1219,7 @@ file corresponding to the module provides a macro that takes care of importing
 the module and retrieving its C API pointers; client modules only have to call
 this macro before accessing the C API.
 
-The exporting module is a modification of the :mod:`spam` module from section
+The exporting module is a modification of the :mod:`!spam` module from section
 :ref:`extending-simpleexample`. The function :func:`spam.system` does not call
 the C library function :c:func:`system` directly, but a function
 :c:func:`PySpam_System`, which would of course do something more complicated in

Doc/extending/newtypes_tutorial.rst

@@ -37,7 +37,7 @@ object.
 
 This sort of thing can only be explained by example, so here's a minimal, but
 complete, module that defines a new type named :class:`Custom` inside a C
-extension module :mod:`custom`:
+extension module :mod:`!custom`:
 
 .. note::
    What we're showing here is the traditional way of defining *static*
@@ -55,7 +55,7 @@ from the previous chapter.  This file defines three things:
 #. How the :class:`Custom` **type** behaves: this is the ``CustomType`` struct,
    which defines a set of flags and function pointers that the interpreter
    inspects when specific operations are requested.
-#. How to initialize the :mod:`custom` module: this is the ``PyInit_custom``
+#. How to initialize the :mod:`!custom` module: this is the ``PyInit_custom``
    function and the associated ``custommodule`` struct.
 
 The first bit is::
@@ -127,7 +127,7 @@ our objects and in some error messages, for example:
    TypeError: can only concatenate str (not "custom.Custom") to str
 
 Note that the name is a dotted name that includes both the module name and the
-name of the type within the module. The module in this case is :mod:`custom` and
+name of the type within the module. The module in this case is :mod:`!custom` and
 the type is :class:`Custom`, so we set the type name to :class:`custom.Custom`.
 Using the real dotted import path is important to make your type compatible
 with the :mod:`pydoc` and :mod:`pickle` modules. ::
@@ -229,7 +229,7 @@ Adding data and methods to the Basic example
 ============================================
 
 Let's extend the basic example to add some data and methods.  Let's also make
-the type usable as a base class. We'll create a new module, :mod:`custom2` that
+the type usable as a base class. We'll create a new module, :mod:`!custom2` that
 adds these capabilities:
 
 .. literalinclude:: ../includes/custom2.c

Doc/install/index.rst

@@ -374,7 +374,7 @@ will expand this to your home directory::
 
 To make Python find the distributions installed with this scheme, you may have
 to :ref:`modify Python's search path <inst-search-path>` or edit
-:mod:`sitecustomize` (see :mod:`site`) to call :func:`site.addsitedir` or edit
+:mod:`!sitecustomize` (see :mod:`site`) to call :func:`site.addsitedir` or edit
 :data:`sys.path`.
 
 The :option:`!--home` option defines the installation base directory.  Files are

Doc/tools/.nitignore

@@ -4,14 +4,12 @@
 
 Doc/c-api/allocation.rst
 Doc/c-api/apiabiversion.rst
-Doc/c-api/arg.rst
 Doc/c-api/bool.rst
 Doc/c-api/buffer.rst
 Doc/c-api/bytes.rst
 Doc/c-api/capsule.rst
 Doc/c-api/cell.rst
 Doc/c-api/code.rst
-Doc/c-api/codec.rst
 Doc/c-api/complex.rst
 Doc/c-api/conversion.rst
 Doc/c-api/datetime.rst