Fix a typo in mathematical-operations.md (#32855)

"Especial" isn't an English word. I tried replacing it with the correct "especially", but I think it sounds cleaner this way.

Author: TheLostLambda

doc/src/manual/mathematical-operations.md

@@ -252,7 +252,7 @@ julia> NaN > NaN
 false
 ```
 
-and can cause especial headaches with [arrays](@ref man-multi-dim-arrays):
+and can cause headaches when working with [arrays](@ref man-multi-dim-arrays):
 
 ```jldoctest
 julia> [1 NaN] == [1 NaN]