bad_keywords.txt: fix word boundary from PR#427
bad_keywords.txt: fix word boundary from PR#427

Based on discussion with Glorfindel, capturing a single mistake is probably less important than covering a recurring pattern, so lose the single mistake and cover half a dozen or so samples from Metasmoke instead.

http://chat.stackexchange.com/transcript/message/34648436#34648436

Charcoal-SE/SmokeDetector,Charcoal-SE/SmokeDetector