Add syntax highlighting for Swift DocC Tutorial files

[Padmashree06]

Description

This PR adds:

• Syntax highlighting for .tutorial files, including directives with and without arguments (@Step, @Tutorial(...), etc.)
• @Comment { } blocks highlighted separately as comments
• Auto-closing for braces, parentheses, quotes and backticks, along with corrected folding markers.

Issue: #1331

Tasks

• Required tests have been written
• Documentation has been updated
• Added an entry to CHANGELOG.md if applicable

[matthewbastien]

The unacceptable language check doesn't like the use of the word master in syntaxes/tutorial.tmLanguage.json. You'll have to add that file to the .unacceptablelanguageignore file.

[matthewbastien]

Given that it seems like adding a Swift DocC Markdown language type is going to be more involved than we first thought, perhaps we should split this into two separate PRs. One for Swift DocC Tutorial syntax and another for Swift DocC Markdown.

[Padmashree06]

Given that it seems like adding a Swift DocC Markdown language type is going to be more involved than we first thought, perhaps we should split this into two separate PRs. One for Swift DocC Tutorial syntax and another for Swift DocC Markdown.

Yes the syntax highlighting for Swift DocC Markdown has been moved to a separate PR - #2327

[matthewbastien]

Just one more thing before this is good to go: can you add an entry to the changelog for this?

[Padmashree06]

Just one more thing before this is good to go: can you add an entry to the changelog for this?

I have added it to changelog!

[matthewbastien]

Thank you!

[Padmashree06]

Thank you for merging!!