t7005-editor: Use $SHELL_PATH in the editor scripts

The test sets up various shell scripts and uses them as commit message
editors.  On Windows, we need a shebang line in order to recognize the
files as executable shell scripts.  This adds it.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>

t/t7005-editor.sh

@@ -7,6 +7,7 @@ test_description='GIT_EDITOR, core.editor, and stuff'
 for i in GIT_EDITOR core_editor EDITOR VISUAL vi
 do
 	cat >e-$i.sh <<-EOF
+	#!$SHELL_PATH
 	echo "Edited by $i" >"\$1"
 	EOF
 	chmod +x e-$i.sh