Sync to upstream/release/527 (luau-lang#491)

Sync to upstream/release/527 (luau-lang#481)

Add documentation for generalized iteration (luau-lang#475)

Sync to upstream/release/525 (luau-lang#467)

Sync to upstream/release/524 (luau-lang#462)

Sync to upstream/release/523 (luau-lang#459)

Sync to upstream/release/522 (luau-lang#450)

Merge branch 'merge'

Sync to upstream/release/520 (luau-lang#427)

Sync to upstream/release/519 (luau-lang#422)