Rollup merge of #5724 - ebroto:5697_const_result_option, r=Manishearth

redundant_pattern_matching: avoid non-`const fn` calls in const contexts

changelog: Avoid suggesting non-`const fn` calls in const contexts in [`redundant_pattern_matching`]

Fixes #5697

diff --cc clippy_lints/src/redundant_pattern_matching.rs
Simple merge