Sync triangle and add stub

[BNAndras]

This syncs the docs, metadata, and tests for triangle. This adds two tests for scalene triangles that check other combinations of the two sides being equal. I also added an non-compiling stub that gives the student the minimum interface needed to pass the tests.

After this, there are 37 exercises where configlet is reporting one or more tests missing since the test.toml files were last updated.

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

For more information, refer to the documentation. If you are unsure whether to add the message or not, please ping @exercism/maintainers-admin in a comment. Thank you!

[kotp]

With the caveat.

[kotp]

Suggested change

	end.
	end.

Last line is exceptional with a missing EOL.

[BNAndras]

Other files in this repo don’t end with a blank line though so the file is fine as written.

[kotp]

I have not been vigilant enough, then. Just because the others are wrong, doesn't mean that we should not fix that. ;)

[kotp]

This is a text file, as such it should be consistent with its termination of lines. Otherise I have to check and fix it when I concatenate information later. (Headings end up being trailing the last "line" of a file when the last "line" ends with EOL plus more characters.) Or I have to check on the rendering for something I really should not have to check for.

[BNAndras]

Embarcadero is now coming after me for a licensing issue related to my Exercism work. Therefore, this is my final contribution involving Delphi Pascal code.

[rpottsoh]

Licensing issue related to Exercism?

[BNAndras]

Indirectly. It’s related to a Delphi 11 Community Edition license I obtained two years ago when I was first taking a look at Delphi Pascal track here.

[rpottsoh]

@BNAndras unless you are profiting by the CE license I don't see what the issue would be as it relates to Exercism and the Delphi track specifically. At any rate, thanks for the work you have put in.