Fix duplicate text in multiple tag search

[micahellison]

Fixes #926.

The pretty print feature (#842) highlights all tags by default, but if you search for a particular tag, it only highlights that tag. However, when searching for multiple tags, it would show the entire title and body once for each tag searched for.

This PR removes that selective highlighting (so all tags are highlighted regardless of what you've searched for) and adds a test that catches the duplication bug.

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?
• Have you written new tests for your core changes, as applicable?

[wren]

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