* Fix typos
* Document Cachable* -> Cacheable* rename as v4 breaking change
Adds the response-cache model rename to the change register, per
maintainer decision to skip compatibility aliases in favor of clear
documentation.
* Skip invalid Before import in doc test; use inline codespell ignore
The Cachable* -> Cacheable* breaking-change entry showed the old,
now-invalid import for contrast, which the doc-example test picked up
as a real import and flagged as a regression. Comment out the
deliberately-broken "Before" line (matching the McpError entry just
above it) so only the working "After" import is exercised.
Also swap the blanket codespell ignore-words-list entry for a
narrower inline `codespell:ignore` directive on the one line that
needs it, so codespell keeps flagging "cachable" everywhere else.
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Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>