Fix author extraction for single-line declarations(#4229)

[alok1304]

Fixes #4229

Currently, I did these things:

1. Split tokens on colons (:)

Previously, entries like Author:Frankie.Chu were treated as a single token. I updated the tokenizer to split on : so that Author and Frankie.Chu are recognized as separate tokens.

2. Remove leading plus sign from author token

There is no support for leading + in author token like #+AUTHOR: Lee Hinman, I removed the leading plus sign from the author token +AUTHOR. There are 45k+ file used these this, these .org file see https://github.com/search?q=%22%2Bauthor%3A%22&type=code&p=5

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)

Signed-off-by: Alok Kumar alokkumarjipura9973@gmail.com

[alok1304]

still in Author:Frankie.Chu author is not detect because of this single token Frankie.Chu, I am trying to add this in GRAMMER
https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/cluecode/copyrights.py#L3414 I add

    AUTHOR: {<AUTH>  <NNP|NN>}

this worked fine but due to this, we got many false positive detections. like for author be etc..