Simplified the explanation for the Variable LILYPOND_GC_YIELD
This selects the language for the warning messages.
@item LILYPOND_GC_YIELD
-With this variable the memory footprint and performance can be
-adjusted. It is a percentage tunes memory management behavior. With
-higher values, the program uses more memory, with smaller values, it
-uses more CPU time. The default value is @code{70}.
+A variable, as a percentage, that tunes memory management behavior. A higher values means the program uses more memory, a smaller value means more CPU time is used. The default value is @code{70}.
@end table