Proposal : Add time spent to a merge request / issue in a commit message

Proposal

This proposal is based on #16543 (comment 259395262) and more generally on some other issues : Sources : #16543 (closed) / gitlab-foss#28044 (closed)

Desc

The goal is to simplify the tracking of the time spent without manually add a comment on a merge request or issue for example.

Can we attach and modify the time spent of a MR/Issue directly in a commit message ?

# Referencing the Merge Request and add 1h and 30min
!150@+1h30m 

# Referencing the issue and add 5min.
#25@+5m

We could use the @ delimiter after referencing an issue or MR without space character to indicate the time spent based on the /spend or /estimate convention.