Merge `a111b474` into `release/6.0`

[ahoppen]

Merge the following PRs into release/6.0

• https://github.com/apple/sourcekit-lsp/pull/1486
• https://github.com/apple/sourcekit-lsp/pull/1487
• https://github.com/apple/sourcekit-lsp/pull/1484
• https://github.com/apple/sourcekit-lsp/pull/1489
• https://github.com/apple/sourcekit-lsp/pull/1490
• https://github.com/apple/sourcekit-lsp/pull/1448
• https://github.com/apple/sourcekit-lsp/pull/1492
• https://github.com/apple/sourcekit-lsp/pull/1497
• https://github.com/apple/sourcekit-lsp/pull/1485

[ahoppen]

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