[nrc.en.mtnt] Further revisions to wordlist

[DavidLRowe]

In February 2024, revisions were made to the wordlist (issue #178 partially addressed by pull request #221). This issue attempts to collect the unaddressed parts of the issue and the comments made on the pull request.

Residue from issue #178 :
Add common words such as:

• Covid (the original wordlist gathered from reddit was pre-covid)
• Qantas (airline) (and a number of other brands!)
• Coronavirus

Suggestion from comments in PR #221 :

• Make separate file(s) for proper names and acronyms
• Add back two- and three-letter words (See "changed_or_deleted.txt" file linked in the comments of that PR)
• Include word endings (-ed, -s, -ing).