Formatting for object descriptions.

[darvil82]

Allow descriptions of objects, such as Argument's or Command's to have richer information. At the moment, when printing the description on the help view, both the description specified to the argument and the one of the argument type are shown.
This is great, but it would be neat to allow more customization, such as being able to specify formatting semantics, like {@link args.arg1} or {@link cmds.mySubcmd1}.

Example:

Argument.create("test").description("Interesting argument. See also {@link args.arg1}.")

When being printed on the help, this is what would be shown:

--test:
   Interesting argument. See also --arg1.

--arg1 would be shown with the color that represents it. And also, if it had multiple names, these would be shown like --arg1/argument1. Basically the argument representation that is normally shown for each argument.

Formatters ideas:

• @link: Basically a "reference" to the specified element, as explained above.
• @from: Inlines the description of the selected element into the current one.

Selectors:

After one of the formatters above is specified, a selector can be used to indicate the element to select (Command, argument, etc.):

• args.<arg>: The argument with the specified name.
  • <arg>.type: The argument type of the argument. At the moment the description of the type is automatically added. So with this change the user would need to add @from !.type. (! explained below).
• cmds.<cmd>: The command with the specified name.
  • Since a Command contains more arguments, this can be chained like cmds.<cmd>.args.<arg>.
• groups.<grp>: The group with the specified name.
• !: This selects the current element that is generating the description. For example, if the description of an argument named "foo" is set to @link !, this would be equal to @link args.foo.

Syntax ideas:

• @link:args.arg1, suggested by @fadeoffical. No spaces required but possible problems when parsing if no spaces are present after it, like desc: @link:args.arg1.. The . could cause problems, but we could probably allow {} wrapping to indicate the formatting more explicitly.
• @link args.arg1, similar to javadocs syntax, though I personally prefer the former!
• <link=args.arg1>, much easier to parse with the eyes. Will go with this one.

[fadeoffical]

You sure you want to pull into main?

[darvil82]

Nah it'll be merged into dev. Forgot to change that.

[fadeoffical]

Lgtm! except the two finals.