revset: add test for resolution of infix/suffix ambiguity of x^:y This is the test for 805651777188, and I'm going to fix the failure of 'x^A' where 'revsetalias.A=:y'.

parser: remove unused binding parameter from suffix action Because a suffix action never takes subsequent tokens, it should have no binding strength nor closing character. I've tried if this value could be used to resolve infix/suffix ambiguity of x^:y, but it appears not. So I decided to resend this patch.

extensions: add unwrapfunction to undo wrapfunction Before this patch, we don't have a safe way to undo a wrapfunction because other extensions may wrap the same function and calling setattr will undo them accidentally. This patch adds an "unwrapfunction" to address the issue. It removes the wrapper from the wrapper chain, and re-wraps everything, which is not the most efficient but short and easy to understand. We can revisit the code if we have perf issues with long chains. The "undo" feature is useful in cases like wrapping a function just in a scope. Like, having a "select" command to interactively (using arrow keys) select content from some output (ex. smartlog). It could wrap "ui.label" to extract interesting texts just in the "select" command.