pidgin/pidgin

Fix some spelling errors
release-2.x.y
2021-01-21, Richard Laager
5201d33e8999
Fix some spelling errors

This is #438, but for the release-2.x.y branch. There were more errors in release-2.x.y (which is where I was starting) than default.

Testing Done:
I looked at the diff.

Reviewed at https://reviews.imfreedom.org/r/439/
installed_m4=purple.m4
EXTRA_DIST=$(installed_m4)
m4datadir=$(datadir)/aclocal
m4data_DATA=$(installed_m4)