Upstream our grammar fixes to `dlang/dlang.org`

[CyberShadow]

When tree-sitter-d does not behave correctly due to an error in the language specification, the workflow for fixing the problem is as follows:

• Make the fix in the dlang.org fork/branch used to generate the tree-sitter grammar
• Re-run the conversion program, re-creating the grammar.js file on the generated branch, and commit any changes plus the submodule update
• Merge the generated branch into the master branch
• Observe the effect of the change (test suite fallout)
• Amend the merge commit with any necessary fix-ups, such as conflicts and test-suite updates
• If the grammar change has the desired expected effect, submit it upstream.

Previously, all upstream submissions have been using a linear history. However, as the complexity of the fixes has continued to rise from trivial DDoc syntax fixes to non-trivial grammar changes, reviewing a linear history has become increasingly impractical. For this reason, individual grammar fixes ought to be submitted upstream as individual pull requests.

As our fixes are no longer contained within a single PR, this issue will be used to track the submission status of our grammar fixes:

• [x] https://github.com/dlang/dlang.org/pull/3055
• [x] https://github.com/dlang/dlang.org/pull/3033
• [x] https://github.com/dlang/dlang.org/pull/3034
• [x] https://github.com/dlang/dlang.org/pull/3035
• [x] https://github.com/dlang/dlang.org/pull/3036
• [x] https://github.com/dlang/dlang.org/pull/3037
• [x] https://github.com/dlang/dlang.org/pull/3038
• [x] https://github.com/dlang/dlang.org/pull/3039
• [x] https://github.com/dlang/dlang.org/pull/3040
• [x] https://github.com/dlang/dlang.org/pull/3041
• [x] https://github.com/dlang/dlang.org/pull/3042
• [x] https://github.com/dlang/dlang.org/pull/3043
• [x] https://github.com/dlang/dlang.org/pull/3044
• [x] https://github.com/dlang/dlang.org/pull/3045
• [x] https://github.com/dlang/dlang.org/pull/3046
• [x] https://github.com/dlang/dlang.org/pull/3047
• [x] https://github.com/dlang/dlang.org/pull/3048
• [x] https://github.com/dlang/dlang.org/pull/3049
• [x] https://github.com/dlang/dlang.org/pull/3050
• [x] https://github.com/dlang/dlang.org/pull/3051
• [x] https://github.com/dlang/dlang.org/pull/3052
• [x] https://github.com/dlang/dlang.org/pull/3053
• [x] https://github.com/dlang/dlang.org/pull/3054
• [ ] https://github.com/dlang/dlang.org/pull/3059
• [ ] https://github.com/dlang/dlang.org/pull/3068

You can help by reviewing or assisting reviewers of the upstream PRs.