[Groff] bad QE in -ms

[Doug McIlroy]

The -ms macro QE typically draws a misleading diagnostic, "unbalanced QE".
This breaks old documents that expect QP-QE (quoted paragraph) to narrow
the text and then restore it. The groff QE does not restore.

In fact, QE is aliased to RE, which means it will cause other trouble
for a quoted paragraphs inside an RS-RE relative indent.

I guess the rationale for deviating from previous practice was to make
quoted paragraphs like other kinds of paragraph, which don't have end
macros.

If it is desired retain this difference between groff and heirloom
troff, a safer implementation would be to warn and behave like LP.
This is likely to do the proper restoration.

.als QE @QE

.de @QE
address@hidden "legacy QE taken as LP"
.LP
..

Doug