Merge `main` into `release/6.0`

[ahoppen]

Merge the following PRs to release/6.0:

• https://github.com/apple/sourcekit-lsp/pull/1211
• https://github.com/apple/sourcekit-lsp/pull/1415
• https://github.com/apple/sourcekit-lsp/pull/1416
• https://github.com/apple/sourcekit-lsp/pull/1428
• https://github.com/apple/sourcekit-lsp/pull/1411
• https://github.com/apple/sourcekit-lsp/pull/1431
• https://github.com/apple/sourcekit-lsp/pull/1432
• https://github.com/apple/sourcekit-lsp/pull/1435
• https://github.com/apple/sourcekit-lsp/pull/1429

[ahoppen]

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