Improve error reporting for "relevant bindings" again (Trac #8233)
This patch makes a number of related improvements: * Displays relevant bindings in innermost-first order. The inner ones are closer to the error. * Does not display syntactically top-level bindings, unless you say -fno-max-relevant-bindings. This is what Trac #8233 was mainly about * Makes the TopLevelFlag in a TcIdBinder really mean "syntactically top level". It was a bit vague before. There was some associated simplification, because we no longer need to pas a TopLevelFlag to tcMonoBinds and friends.