[Groff] tbl bug[s]

[Larry McVoy]

This is in groff-1.15, if someone can tell me it is already fixed I'll
promptly upgrade.

Take the following table and groff -t it and you will see two things:

a) The baseline for the text in the T{ }T is different from the other 
   baselines.

b) The T{ }T changes the font.  If I lift the .ft above the table then
   it does not but that strikes as the wrong thing.

.ps 16
.vs 18
.TS
expand box;
cw(.7i)|cw(4.0i)|rw(1.2i)|rw(1.2i)
c|l|r|r.
.ft HB
Qty     Description     Price   Total 
_
.ps -2
.vs -2
.sp .5
XX      T{
 Some text Some text Some
T}      $1,550  $27,900
XX      Some text Some text Some        $1,550  $27,900
.TE