spec is wrong for event_match.pattern push rule condition

[richvdh]

https://matrix.org/docs/spec/client_server/r0.6.1#conditions says:

Patterns with no special glob characters should be treated as having asterisks prepended and appended when testing the condition.

This sounds like a disasterous idea (since it would mean rules with a condition of type == 'm.room.message' would also match events of type org.example.m.room.message). Fortunately it appears to be untrue.

(that said: synapse does implement some magic when the match key is content.body, where it searches for the search term anywhere in the event body, but also only matches complete words)

[richvdh]

(the relevant code starts here: https://github.com/matrix-org/synapse/blob/v1.15.0/synapse/push/push_rule_evaluator.py#L132)

[richvdh]

fixed by #3690