imap-simple: sync description format of search()
imap-simple: sync description format of search()

The description of the `search()` method uses the phrase "in the previously opened mailbox", which is inconsistent with what's used in `onmail()`, `append()` and `moveMessage()`, i.e. "in the currently open mailbox". This change rewords the first passage to match the other ones.
mcliment/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,borisyankov/DefinitelyTyped,markogresak/DefinitelyTyped,borisyankov/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,dsebastien/DefinitelyTyped,georgemarshall/DefinitelyTyped