Release v4.158.0

Changed

• propose-source with formatting: "PreserveExactSource" now writes your source text exactly as supplied, including structural edits such as an added import or an appended feature. Comments, column alignment, blank lines and line endings are kept, a replaced document keeps its BOM policy, and the proposal goes through the same parse, identity, reference and compilation checks as canonical printing. CanonicalizeTouchedDocuments still reprints touched documents canonically, and propose-ast is unchanged. (#708)
• A propose-source structural change refused under PreserveTrivia now names PreserveExactSource as the way to keep the supplied text. (#708)