Fix typo

Fixes #1176

CppCoreGuidelines.md

@@ -17765,7 +17765,7 @@ The syntax and techniques needed are pretty horrendous.
 ##### Reason
 
 Template metaprogramming is hard to get right, slows down compilation, and is often very hard to maintain.
-However, there are real-world examples where template metaprogramming provides better performance that any alternative short of expert-level assembly code.
+However, there are real-world examples where template metaprogramming provides better performance than any alternative short of expert-level assembly code.
 Also, there are real-world examples where template metaprogramming expresses the fundamental ideas better than run-time code.
 For example, if you really need AST manipulation at compile time (e.g., for optional matrix operation folding) there may be no other way in C++.