Unrelated third-party trackers that happened to share a leading
separator run (e.g. __support__, __darkreader__wasEnabledForHost,
__EXT_APP_REFRESH_BLACK_SUB_DOMAINS__) were being merged under
overly broad globs such as __* because templateCandidates emitted
every prefix at each '_' or '-' position without requiring any
fixed anchor.
Add a templateHasFixedAnchor helper and apply it to both
templateCandidates loops and the heuristicTemplate result so
candidates consisting solely of '_', '-', and '*' are rejected.
Signed-off-by: Émile Ré <emile@probo.com>
a5ee0209f8