fix: =$= and =0= motions for calendar view

[celsobenedetti]

Summary

This PR configures the $ and 0 mappings for the calendar view, so they take us to the last/first day of the week.

I just hacked this together to make it work. I'm happy to address any direction this should be taken.

Thank you!

Video demonstrating the problem on master 55b68bb

Kazam_screencast_00016.mp4

Video demonstrating the behavior on this branch

Kazam_screencast_00017.mp4

Related Issues

Closes #986

Changes

Configuring two new mappings for $ and 0 on the calendar view.

Checklist

I confirm that I have:

• Followed the
  Conventional Commits
  specification (e.g., feat: add new feature, fix: correct bug,
  docs: update documentation).
• My PR title also follows the conventional commits specification.
• Updated relevant documentation, if necessary.
• Thoroughly tested my changes.
• Added tests (if applicable) and verified existing tests pass with
  make test.
• Checked for breaking changes and documented them, if any.

[kristijanhusak]

Thanks for the PR! Generally looks good, but there are few edge cases that needs to be handled.

[celsobenedetti]

Thank you! Tested the suggestion locally and could find no bugs.

• tested regular weeks
• tested weeks that don't start on Sun
• tested weeks that don't end on Sat

[kristijanhusak]

Thanks!