Update PsySh from 0.8.5 to 0.8.11

Update PsySh from 0.8.5 to 0.8.11

0.8.11 adds bracketed paste support for readline,
meaning that it can differentiate between
interaction-triggering characters (such as newline
or tab) which have been entered manually, and ones
which have been pasted so their special effect should
be suppressed. Also a bunch of small bugfixes and features.

Release summaries: https://github.com/bobthecow/psysh/releases
All changes: https://github.com/bobthecow/psysh/compare/v0.8.5...v0.8.11?expand=1

There are no dependency changes; I've skimmed the code
changes and all seem harmless.

Change-Id: I33456904787fd86458249ddfbb00c6b55592da07