Bug: YAML rendering still flattened in v0.50.291

Expected: YAML code blocks should preserve line breaks (fixed in #1463 via PR #1516).

Actual: In v0.50.291, YAML blocks are still flattened/collapsed.

Root cause: v0.50.291 appears to be branched from a commit before the YAML fix (PR #1516) was merged. The release notes show v0.50.291 only contains the "What's new? link 404 fix" and does not include the v0.50.279 batch that had the YAML fix.

Evidence:

• PR fix: YAML code blocks collapse newlines due to Prism token white-space (#1463) #1516 fixed this in v0.50.279: "YAML code blocks render with newlines (Prism token spans had white-space: normal collapsing \n). Closes YAML raw rendering still ignores line breaks after #1400 #1463."
• v0.50.291 release only shows 1 PR merged (the 404 fix), missing the 8-PR batch from v0.50.279