Module resolution improvements

[Daniel-Knights]

This PR adds support for resolving module paths using explicit module ids (@module <id>) and implicit module ids, mirroring the same method JSDoc uses. The typescript.moduleRoot config option is still prioritised over these for backwards compact.

This PR also:

• Removes leading ../ path segments from module ids (if a referenced module is located outside the cwd), as they cause errors.
• Resolves /index.js for paths that target the parent directory.

Changes

• Update README
• No longer throw errors for missing typescript.moduleRoot config option, only if present and the provided path doesn't exist
• Use absolute file paths as keys in moduleInfos and fileNodes instead of module ids to simplify setting and accessing
• getImplicitRoot function for when there's no typescript.moduleRoot option or explicit module id
• getModuleId function
• Cache module ids in moduleInfos
• Remove parser param from getDefaultExportName and getDelimiter as it's being passed to the extension param of getModuleInfo

Additional notes

In my opinion, the typescript.moduleRoot config option should be deprecated, as it introduces the risk of a mismatch between what JSDoc considers an existing module id and the id this plugin uses internally.

I was unsure how to add tests for this - open to any suggestions.

[ahocevar]

I think it makes sense to remove the moduleRoot config option, and we can publish a major release with that breaking change. No need to deprecate.

[Daniel-Knights]

Okay, I've removed typescript.moduleRoot

[ahocevar]

Thanks, @Daniel-Knights