Fix typos identified by codespell.

Self test baselines also modified accordingly, due to
one typo found in a string in test code.

include/internal/catch_matchers_generic.hpp

@@ -45,7 +45,7 @@ public:
 
     // The following functions create the actual matcher objects.
     // The user has to explicitly specify type to the function, because
-    // infering std::function<bool(T const&)> is hard (but possible) and
+    // inferring std::function<bool(T const&)> is hard (but possible) and
     // requires a lot of TMP.
     template<typename T>
     Generic::PredicateMatcher<T> Predicate(std::function<bool(T const&)> const& predicate, std::string const& description = "") {