Add missing test and support help options with only the short flag in Help.visibleOptions()

[aweebit]

An extension of #1929 fixing a problem I run into when writing demo code for #1931.

Has been merged with the already approved tiny fixes PR #1930 because the parent #1929 has been merged with it.

Problem

program
  .option('-h, --host')
  .helpOption('-h')
  .outputHelp(); // throws

lib\option.js:17
    this.required = flags.includes('<'); // A value must be supplied when the option is specified.
                          ^

TypeError: Cannot read properties of undefined (reading 'includes')
    at new Option (lib\option.js:17:27)
    at Command.createOption (lib\command.js:500:12)
    at Help.visibleOptions (lib\help.js:79:26)
    at Help.longestOptionTermLength (lib\help.js:197:19)
    at Help.padWidth (lib\help.js:419:14)
    at Help.formatHelp (lib\help.js:349:30)
    at Command.helpInformation (lib\command.js:1988:19)
    at Command.outputHelp (lib\command.js:2028:32)

Solution

Help.visibleOptions() code has been updated to support help options with only the short flag well.

Tests have been added to cover this and other similar use cases.

ChangeLog

Changed

• (from #1929) Breaking: use .createOption() in .helpOption() to support custom option flag extraction

Fixed

• added missing support for help options with only the short flag

[aweebit]

Side note: I don't know if I'm doing it right with the base PR "extensions" and the merges. The commits and file changes look really cluttered now. If it's appropriate and if #1929 can't be merged right now, a good idea might be to create a temporary branch based off #1929 and make it the base for all PRs building on it (#1931, #1934, #1935). This PR would then only contain the last two commits which are the relevant ones, for example, making it much simpler to review the changes.

[shadowspawn]

Side note: I don't know if I'm doing it right with the base PR "extensions" and the merges. The commits and file changes look really cluttered now.

With 20/20 hindsight I can confidently say this was not the right approach. 😆

Some parts this have been approved separately, and some parts have been rejected separately. Closing this one as too messy to try and review what is left.