add usage-strings ci check and amend remaining usage strings

This patch series completely fixes #636.

The issue is about amending the usage-strings (for command flags such as -h, -v etc.) which do not follow the style convention/guide. There was a PR
[https://github.com/gitgitgadget/git/pull/920] addressing this issue but as Johannes [https://github.com/dscho] said in his comment
[https://github.com/gitgitgadget/git/issues/636#issuecomment-1018660439],
there are some files that still have those kind of usage strings. Johannes also suggested to add a CI check under ci/test-documentation.sh to check the usage strings.

In this version, comments added and the From field of the first commit message is updated (i.e. "Abhradeep Chakraborty" instead of "Abhra303")

Changes since v2:

1. split the single commit into two logically separated commits ( one addressing amending of usage strings and another is for adding the style checks to parse_options_check())
2. the checks are simplified.

Changes since v1:

1. remove check-usage-strings.sh
2. remove CI check
3. add checks to parse-options.c
4. modify t/t1502-rev-parse-parseopt.sh to pass the test

Until v1:

A shell script check-usage-strings.sh was introduced to check the usage-strings. CI check for the same was also introduced.

Abhradeep Chakraborty (2):
amend remaining usage strings according to style guide parse-options.c: add style checks for usage-strings

 builtin/bisect--helper.c      |  2 +-
 builtin/reflog.c              |  6 +++---
 builtin/submodule--helper.c   |  2 +-
 diff.c                        |  2 +-
 parse-options.c               | 11 +++++++++++
 t/helper/test-run-command.c   |  6 +++---
 t/t1502-rev-parse-parseopt.sh |  4 ++--
 7 files changed, 22 insertions(+), 11 deletions(-)

base-commit: e6ebfd0e8cbbd10878070c8a356b5ad1b3ca464e
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1147%2FAbhra303%2Fusage_command_amend-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1147/Abhra303/usage_command_amend-v4
Pull-Request: https://github.com/gitgitgadget/git/pull/1147

Range-diff vs v3:

1: f425e36b7ea ! 1: dc200d098ae amend remaining usage strings according to style guide
@@
## Metadata ##
-Author: Abhra303 <[email protected]>
+Author: Abhradeep Chakraborty <[email protected]>

## Commit message ##
amend remaining usage strings according to style guide
2: 9d42bdbff6c ! 2: e1c5a325826 parse-options.c: add style checks for usage-strings

     @@ parse-options.c: static void parse_options_check(const struct option *opts)
       		default:
       			; /* ok. (usually accepts an argument) */
       		}
     ++
     ++		// OPTION_GROUP should be ignored
     ++		// if the first two characters of the help string are uppercase, then assume it is an
     ++		// acronym (i.e. "GPG") or special name (i.e. "HEAD"), thus allowed.
     ++		// else assume the usage string is violating the style convention and throw error.
      +		if (opts->type != OPTION_GROUP && opts->help &&
      +			opts->help[0] && isupper(opts->help[0]) &&
      +			!(opts->help[1] && isupper(opts->help[1])))

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