cleanup: remove pointless r-prefixes on double-quoted strings
This is only double-quoted strings. I'll do single-quoted strings as a
second step. These had existed because our source transformer didn't
turn r"" into b"", so we had tagged some strings as r-strings to get
"native" strings on both Pythons. Now that the transformer is gone, we
can dispense with this nonsense.
hg locate 'set:added() or modified() or clean()' | egrep '.*\.py$' | xargs egrep --color=never -n -- \[\^a-z\]r\"\[\^\"\\\\\]\*\"\[\^\"\]
in an emacs grep-mode buffer, and then used a keyboard macro to
iterate over the results and remove the r prefix as needed.
skip-blame removing unneeded r prefixes left over from Python 3 migration.
Differential Revision: https://phab.mercurial-scm.org/D7305