[Groff] Divert into string variable

[Carsten Kunze]

Hello,

is it safe to divert into a string variable?  That means instead of:

.br
.di A
...text...
.br
.di
.A

use something like:

.br
.di A
...text...
.br
.di
...\*A...

The 4.4BSD mdoc macros use this in the macro .x2. The string is even 
interpolated in fill mode there...  It works somehow but not really reliable.  
I'm not sure if this usage is bug in 4.4BSD mdoc or if there is a bug in the 
diversion implementation (Heirloom in this case).  This usage is IMHO not 
documented in the troff manual § 7.4 or groff manual § 5.25.

Carsten