Remove groff/tmac/mm.diff - it is just a small file containing a context

diff that was probably mistakenly committed when the package was brought in.

gnu/usr.bin/groff/tmac/mm.diff

@@ -1,70 +0,0 @@
-*** tmac.m-	Thu Aug  2 14:49:57 1990
---- tmac.m	Thu Aug  2 14:55:40 1990
-***************
-*** 744,749 ****
-  .fi
-  .di >A
-! \!.cs 3 48
-! .if !0\\$1-\\n(:d .if !\\n(:f \\*(}y\\$4\\\\f3\\a\\\\fP\\*(}3
-  .if !0\\$1-\\n(:d .if \\n(:f \\*(}y\\$4\\t\\*(}3
-  .if 0\\$1-\\n(:d \\*(}y\\$4\\*(}3
---- 744,749 ----
-  .fi
-  .di >A
-! .cs 3 48
-! .if !0\\$1-\\n(:d .if !\\n(:f \\*(}y\\$4\?\f3\?\\a\?\fP\?\\*(}3
-  .if !0\\$1-\\n(:d .if \\n(:f \\*(}y\\$4\\t\\*(}3
-  .if 0\\$1-\\n(:d \\*(}y\\$4\\*(}3
-***************
-*** 750,754 ****
-  .br
-  \!.br
-! \!.cs 3
-  .di
-  .br
---- 750,754 ----
-  .br
-  \!.br
-! .cs 3
-  .di
-  .br
-***************
-*** 1397,1406 ****
-  .tr ,+
-  .tr |.
-- .ie \\nE \{\
-- |ds\ >8\ \f3\\\\$1+\\\\$2+\\\\$3+\\\\$4+\\\\$5+\\\\$6+\\\\$7+\\\\$8+\\\\$9\fP
-- 'br \}
-- .el \{\
-  |ds\ >8\ \\\\$1+\\\\$2+\\\\$3+\\\\$4+\\\\$5+\\\\$6+\\\\$7+\\\\$8+\\\\$9
-- 'br \}
-  .br
-  \!.br
---- 1397,1401 ----
-***************
-*** 1407,1410 ****
---- 1402,1406 ----
-  .tr ,,++||
-  .di
-+ .asciify >A
-  \\..
-  .>7 \\*(>1
-***************
-*** 1424,1429 ****
---- 1420,1427 ----
-  .tr ||++
-  .di
-+ .asciify >7
-  .de >A
-  .de >T
-+ .if \\nE .ft 3
-  .if \\\\n(.$ \\\\$1
-  .if \\\\n(.$-1 \\\\$2
-***************
-*** 1435,1438 ****
---- 1433,1437 ----
-  .if \\\\n(.$-7 \\\\$8
-  .if \\\\n(.$-8 \\\\$9
-+ .if \\nE .ft
-  \\\\..
-  \\..