Update starts_with, ends_with and contains to new API design

[jdunkerley]

Pull Request Description

• Updated Text.starts_with, Text.ends_with and Text.contains to new simpler API.
• Added a Case_Sensitivity.Default and adjusted Table.distinct to use it by default.
• Fixed a bug with Data.fetch on an HTTP error.
• Improved SQLite Case Sensitivity control in distinct to use collations.

Checklist

Please include the following checklist in your PR:

• The documentation has been updated if necessary.
• All code conforms to the
  Scala,
  Java,
  and
  Rust
  style guides.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed: Enso GUI was tested when built using BOTH
    ./run ide build and ./run ide watch.

[radeusgd]

Awesome!

I really like the simplicity of the new API and also the fact that we now express default handling by an explicit Atom instead of Nothing.

Just one code style suggestion - I think the locale check should now become the responsibility of prepare_distinct.

I'd add a test checking it and mark it pending in Postgres - so that we have it clearly documented that this feature is pending. I think it is worth keeping such 'documentation-test' as if we get some bug report in the future at least we'll be more aware that this was a conscious decision to defer this instead of being confused that it is a bug.

And I think we should be explicit that forcing case sensitivity in Postgres is currently not supported - otherwise a user may use it and be confused why it doesn't work. Especially as this workaround does not affect the default usage.

[radeusgd]

I'm so fond of this change! Meaningful constructors are always much better over Nothing carrying thousands of meanings.