This fixes lots of typos throughout the tree. Can this be committed to
trunk as obvious?

I've bootstrapped the C and C++ compilers, but not Ada, and of course
not compiled all the target changes in gcc/config/*

Is one big commit OK, or one per-ChangeLog? Or something else?

(Currently I have one commit per ChangeLog, but can easily squash it
to one commit.)

I'm sure there are many more, because this patch comes from an old
branch I found lying around on an old machine. I did this back in
2013 but never committed it:
https://gcc.gnu.org/ml/gcc-patches/2013-07/msg00226.html