Add missing hover text for "edit task description" button

Summary

The button to edit a task is an icon without the hover text.

Related:

• #363007 (closed)

Steps to reproduce

https://gitlab.com/gitlab-org/gitlab/-/work_items/118880214

Ignored parts of the template

What is the current bug behavior?

What is the expected correct behavior?

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

The hover text should say, for example, Edit.

After the button is edited, update the steps in https://docs.gitlab.com/ee/user/tasks.html#edit-a-task

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