Don't .ds <= and >=, use \(<= and \)>= directly

The symbols work fine even with CRT.MAC.  In fact, they've been used
by Food.t since Empire 2.

info/CRT.MAC

@@ -18,8 +18,6 @@
 .\" Start out correctly
 .nr CS 0
 .\" Special strings for special characters, including smart quotes.
-.ds <= <=
-.ds >= >=
 .ds Q \&"
 .ds U \&"
 .pl 23v         \" Page length: 23 lines

info/Innards.t

@@ -146,14 +146,14 @@ Collect the taxes, pay the military
 /* plague */
 If p_stage = \*Qthird\*U kill off a bunch of people,
    alert the owner and the news and decrement p_time by dt.
-   If p_time \*(<= 0 set p_stage = zero (plague has burned itself out).
+   If p_time \(<= 0 set p_stage = zero (plague has burned itself out).
 If p_stage = \*Qsecond\*U report
    to the owner and the news and decrement p_time by dt.
-   If p_time \*(<= 0 set p_stage = \*Qthird\*U
+   If p_time \(<= 0 set p_stage = \*Qthird\*U
       and randomly reset p_time in the range of etu_per_update to
       (etu_per_update * 2).
 If p_stage = \*Qfirst\*U decrement p_time by dt.
-   If p_time \*(<= 0 set p_stage = \*Qsecond\*U
+   If p_time \(<= 0 set p_stage = \*Qsecond\*U
       and randomly reset p_time in the range of etu_per_update to
       (etu_per_update * 2).
 If p_stage = zero and a random number in the range 0-99

info/TROFF.MAC

@@ -18,8 +18,6 @@
 .\" Start out correctly
 .nr CS 0
 .\" Special strings for special characters, including smart quotes.
-.ds <= \(<=
-.ds >= \(>=
 .ds Q ``
 .ds U ''
 .pl 11i                 \" Page length - environment 0