Auto merge of #12959 - lnicola:rainbows-again, r=lnicola
Auto merge of #12959 - lnicola:rainbows-again, r=lnicola

Fix `test_rainbow_highlighting` gate

CC https://github.com/rust-lang/rust-analyzer/pull/12903#pullrequestreview-1058906953

rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer