fix: exempt doc comments from the code-comment budget

Rustdoc, JSDoc, NatSpec and docstrings document a surface for callers and
are read by tooling — NatSpec ends up in contract metadata. The rule read
as an instruction to delete them, and the linter blocked a legitimate
rustdoc block.

Also: plain block comment bodies were never linted (no per-line marker),
and a literal double-star in a code span was flagged as bold.

Merges the landmine and MUST categories, which said the same thing.

claude-md/code-comments.md

@@ -8,10 +8,10 @@ paths:
 Budget: 1-3 lines. Write one only when an agent with the repo and thirty
 seconds of grep would still get it wrong. That means one of:
 
-- a landmine no test catches
+- something that breaks silently — no test catches it, or a caller can
+  break it from outside
 - a fact not in the repo (deployed bytecode, chain quirk, library bug)
 - a unit or epoch the type cannot carry (wei, ms, 18-dp)
-- a MUST or MUST NOT a caller can break
 
 Good:
 
@@ -22,3 +22,11 @@ Everything else: delete. Design rationale and rejected alternatives go in
 MUST / NEVER.
 
 Deleting a comment is cheap and reversible. When unsure, delete.
+
+### Doc comments are not this
+
+Rustdoc `///`, JSDoc `/** */`, Solidity NatSpec `@notice`/`@dev`, Python
+docstrings: different genre, budget does not apply. They document a surface
+for callers who cannot see the body, and tooling reads them — NatSpec ends
+up in contract metadata. Follow the language's convention, and never strip
+them to satisfy the budget above.