Static grep assertions on pure JS modules fail on renames that change
nothing and pass on edits that change behavior. Following the PR #303
method, each removed fragment was verified by breaking the behavior it
describes and confirming a QtTest goes red. Six coverage gaps found
this way gained a failing-first test before their assertion was
removed. Four UsageDetails assertions are kept: the grapheme comment
and the three reject_* style pins cannot be expressed as runtime tests.

No production code changes. No user-visible change, so CHANGELOG is
untouched.