scripts: kernel-doc: Translate the "Output selection" subsection of OPTIONS

Aim: unified POD, user more satisfied, script better structured

The plurals in -function and -nosymbol are corrected to singulars.
That's how the script works now. I think this describes the syntax better.
The plurar suggests multiple FILE arguments might be possible. So this
seems more coherent.

Other notes:
- paragraphing correction
- article correction

Signed-off-by: Tomasz Warniełło <tomasz.warniello@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Disliked-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20220218181628.1411551-7-tomasz.warniello@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

scripts/kernel-doc

@@ -83,19 +83,6 @@ sub usage {
     my $message = <<"EOF";
 Usage: $0 [OPTION ...] FILE ...
 
-Output selection (mutually exclusive):
-  -export		Only output documentation for symbols that have been
-			exported using EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL()
-                        in any input FILE or -export-file FILE.
-  -internal		Only output documentation for symbols that have NOT been
-			exported using EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL()
-                        in any input FILE or -export-file FILE.
-  -function NAME	Only output documentation for the given function(s)
-			or DOC: section title(s). All other functions and DOC:
-			sections are ignored. May be specified multiple times.
-  -nosymbol NAME	Exclude the specified symbols from the output
-		        documentation. May be specified multiple times.
-
 Output selection modifiers:
   -no-doc-sections	Do not output DOC: sections.
   -enable-lineno        Enable output of #define LINENO lines. Only works with
@@ -2591,4 +2578,33 @@ found on PATH.
 
 =back
 
+=head2 Output selection (mutually exclusive):
+
+=over 8
+
+=item -export
+
+Only output documentation for the symbols that have been exported using
+EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL() in any input FILE or -export-file FILE.
+
+=item -internal
+
+Only output documentation for the symbols that have NOT been exported using
+EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL() in any input FILE or -export-file FILE.
+
+=item -function NAME
+
+Only output documentation for the given function or DOC: section title.
+All other functions and DOC: sections are ignored.
+
+May be specified multiple times.
+
+=item -nosymbol NAME
+
+Exclude the specified symbol from the output documentation.
+
+May be specified multiple times.
+
+=back
+
 =cut