Add changes from 2021.3.3

[seanbudd]

Summary of the issue:

Initially changes for 2021.3.1 were delivered to beta, subsequently it was decided to avoid complications with translations, to make changes directly on RC.
The changes were cherry picked from beta.
There were then several more changes made squashed / merged to RC
These changes need to be cherry picked back into the beta branch.
This was done in #13185

Changes for 2021.3.3 were cherrypicked directly to rc.
But because rc and beta/master have diverged, these changes need to be cherrypicked back to master and beta.
An exchange of merging master and beta has already occurred since the last release.
As a result, these changes need to be cherry-picked directly to master, to get eventually merged to beta.

Description of how this pull request fixes the issue:

• Update the changes file from release-2021.3.3

No other introduced changes from 2021.3.2 and 2021.3.3 need to be cherry-picked back to master.
This is because 2021.3.2 and 2021.3.3 was created from code existing on master.

Testing strategy:

As beta has already had master merged into it, the strategy here is more complicated than in #13185

Check the diff between releases

git diff release-2021.3.1 release-2021.3.3 --stat
 source/api.py                        | 143 +++++++++++++++++++++++++----------
 source/appModuleHandler.py           |  39 ++++++----
 source/appModules/lockapp.py         |  56 +++++++++++---
 source/buildVersion.py               |   2 +-
 source/gui/__init__.py               |   2 +-
 source/gui/contextHelp.py            |   4 +
 tests/system/readme.md               |   4 +-
 tests/system/robot/chromeTests.robot |   1 +
 user_docs/en/changes.t2t             |  18 +++++
 9 files changed, 198 insertions(+), 71 deletions(-

Check the diff between release-2021.3.3 and rc is empty

git diff origin/rc release-2021.3.3

Check what the merge between release-2021.3.3 and master creates,
confirm nothing is missing from this PR that needs to be introduced on master as a cherrypick.

git merge --no-commit origin/rc master

Abort the merge

git merge --abort

Known issues with pull request:

• RC will need to be reset to beta prior to the next release.

Change log entries:

None

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English

[AppVeyorBot]

• PASS: Translation comments check.
• PASS: Unit tests.
• PASS: Lint check.
• FAIL: System tests. See test results for more information.
• Build (for testing PR): https://ci.appveyor.com/api/buildjobs/2issxjbkpwi9t0tw/artifacts/output/nvda_snapshot_pr13388-24806,48fa520e.exe

See test results for failed build of commit 48fa520ed6

[feerrenrut]

Assuming the tests pass.