extensions: refactor function for obtaining disabled extension help The way this worked before was hgext.__index__ was consulted. This file appears to only be present on some Windows distributions. This file contains a dict mapping extension name to its summary line, not its full docstring. The problem with this is that code in the help system was calling this function to resolve help text. If hgext.__index__ was present, only the summary line would be displayed. If not, the full extension help would be printed. This commit changes the function to not use hgext.__index__ such that it always returns the full extension help text. As a result of this change, test-extension.t and test-qrecord.t now pass when run from environments that have an hgext.__index__. Differential Revision: https://phab.mercurial-scm.org/D8344

tests: perform grep manually in test-doctest.py This test has been failing on Windows since 0af56d3ee24c introduced the `hg files` invocation. Specifically, Windows seems to be choking on special characters in the fileset pattern. I believe at least \n and > were causing issues. I attempted various incantations to make the Windows command line parser accept the fileset but couldn't get anything working. I declared bankruptcy and just reimplemented the grepping code in Python. After this change, the test now passes on Windows again. Differential Revision: https://phab.mercurial-scm.org/D8343

tests: prevent printing \r to stdout Like we've done in other recent commits, we need to change sys.stdout on Python 3 to not use os.linesep so output is consistent on Python 3 on Windows. With this change, test-notify.t now passes on Python 3 on Windows! Differential Revision: https://phab.mercurial-scm.org/D8342