The #hashtag functionality within TM comments is not functional

[manjitapandey]

Describe the bug
The comment or message to project creator or manager is not functional for projects and tasks comments. While commenting with #author and #managers, the respective persons are not tagged.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'project details page'
2. Click on '#author'
3. Go to preview
4. See error

Expected behavior
The author should be tagged and depicted with different text format 'bold'.

Screenshots

Additional context
The tagging for individual is functional if we tag user through OSM usernames.

[ramyaragupathy]

Per chat w/ @royallsilwallz @manjitapandey - hashtag highlights works when a sentence begins with the hashtag but when added as a part of sentence it is not highlighted. Please see different combinations listed below.

scenario	current behavior	expected behavior	agreed behavior
just mention #author, with no words before and after	highlight #author, send a mail	highlight #author, send a mail	✅
start a sentence with #author	highlights everything including #author, send a mail	highlight #author, send a mail	no
mention #author somewhere in a sentence	#author not highlighted, but mail sent	highlight #author, send a mail	no
mention #author at the end	#author not highlighted, but mail sent	highlight #author, send a mail	no

cc @prabinoid