clock_getres.2, ctime.3, tgamma.3: srcfix: fix unbalanced .RS/.RE

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/clock_getres.2

@@ -256,6 +256,7 @@ service based upon this clock, including the
 function; nor on the expiration of relative timers based upon this clock.
 Consequently, these time services shall expire when the requested relative
 interval elapses, independently of the new or old value of the clock.
+.RE
 .\"
 .SS Historical note for SMP systems
 Before Linux added kernel support for

man3/ctime.3

@@ -151,7 +151,6 @@ null-terminated string of the form
 .PP
 .in +4n
 .EX
-.RS
 "Wed Jun 30 21:49:08 1993\\n"
 .EE
 ,in

man3/tgamma.3

@@ -70,7 +70,7 @@ outside the poles:
 .PP
 .RS
 Gamma(x) * Gamma(1 \- x) = PI / sin(PI * x)
-.PP
+.RE
 .SH RETURN VALUE
 On success, these functions return Gamma(x).
 .PP