P29 - Attempt to match against a non-topic

Most problems are detected when Inform translates the source text, but this is one of the exceptions, a "run-time problem" which emerges only during play.

The tests 'matches' and 'does not match' can only be used when a snippet is compared with a topic. Topics look like text, being written in double-quotes, but in fact Inform stores them completely differently, and it's important not to mix them up. For instance, if double-quoted text appears in a table column called 'topic', then it'll be a topic: otherwise it will just be plain text.