Rules for writing man pages
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* put two single quotes around an option name like ``--help``.

* put two single quotes with colon around field name like ``field:``.

* put double quotes aground an example of command line, option usage like
  "--langdef=MyLang", referring a section, and a file path.

* use two asterisks for newly introduced conceptual **word** and reserved
  words. The reserved words are

  * "default" in --langmap

* use one asterisk for option parameter like *LANG* in --kind-<LANG> option.

Testing and verification
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* pick reserved words

  - "default"
  - "all"
  - "NONE"
  - '-'

* verify whether + and - can be used as part of language names:

  --langmap
	languages like C++ and/or Objective-C can be specified.

  --languages
	languages like C++ and/or Objective-C can be specified.

* TODO

  - strcasecmp must be used when comparing the name of languages.
