Change jrnl.sh GitHub new issue link to issue template chooser

[micahellison]

I noticed that the support link at the bottom of jrnl.sh points to an empty form for a new GitHub issue. This fix points it to the new issue templates, which should increase the quality of support requests and bug reports.

Checklist

• The code change is tested and works locally.
• Tests pass. Your PR cannot be merged unless tests pass. --
  poetry run behave
• The code passes linting via
  black (consistent code styling). --
  poetry run black --check . --verbose --diff
• The code passes linting via pyflakes
  (logically errors and unused imports). -- poetry run pyflakes jrnl features
• There is no commented out code in this PR.
• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open
  Pull Requests for the same update/change?
• Have you added an explanation of what your changes do and why you'd like
  us to include them?
• [n/a] Have you written new tests for your core changes, as applicable?

[wren]

Good catch!