Fixup return type cannot be a mask

Author: mattkretz

source/numerics.tex

@@ -18930,7 +18930,7 @@
 
 \pnum
 \returns
-A \tcode{basic_simd} or \tcode{basic_simd_mask} object where the $i^\text{th}$
+A \tcode{basic_simd} object where the $i^\text{th}$
 element is initialized to the result of \tcode{mask[$i$] \&\& indices[$i$] <
 ranges::size(in) ? static_cast<T>(ranges::data(in)[indices[$i$]]) :
 T()} for all $i$ in the range \range{0}{I::size()}.