Remove all remaining GParamSpec name and blurb strings (and fix
indentation while we're there), and add G_PARAM_STATIC_STRINGS to all
paramspecs that were lacking it.
We were using g_utf8_strlen() to measure strings for layout, but that
counts combining marks too, and also fails to deal with "fullwidth"
(ie, double-width) CJK characters.
Add a new utility function to do a better job of this (based on code
from vte), and use it everywhere.