[Groff] mom's problem with accents

[Werner LEMBERG]

To get rid of the hard-coded dependency of troff on latin-1, I have
removed all `charXXX' entities from the font description files.  This
has a notable consequence which shows up in warnings like `can't find
character with input code XXX' if .tr isn't handled properly.

Consider the following translation:

  .tr éÉ

This maps input character é onto glyph É, which is identical to glyph
`char201'.  But this glyph intentionally doesn't exist!  Instead,
\[char201] is treated as an input character entity and is itself
mapped onto \['E], and groff doesn't handle translations of
translations.

The right way to write the above translation is

  .tr é\['E]

With other words, the first argument of .tr should be an input
character or entity, and the second one a glyph entity.

Peter, please change the code in mom accordingly.

I will add this to groff.texinfo.


    Werner