doc/utils: add missing `@c man end` title

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/utils.texi

@@ -1031,7 +1031,7 @@ indication of the corresponding powers of 10 and of 2.
 10^24 / 2^70
 @end table
 
-@c man end
+@c man end EXPRESSION EVALUATION
 
 @chapter OpenCL Options
 @c man begin OPENCL OPTIONS