[ASTMatchers][NFC] fix typo 'combarantion' -> 'combination'

Author: vbvictor

clang/include/clang/ASTMatchers/ASTMatchFinder.h

@@ -268,7 +268,7 @@ SmallVector<BoundNodes, 1> match(MatcherT Matcher, ASTContext &Context);
 /// Returns \c NULL if there is no match, or if the matching node cannot be
 /// casted to \c NodeT.
 ///
-/// This is useful in combanation with \c match():
+/// This is useful in combination with \c match():
 /// \code
 ///   const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"),
 ///                                                 Node, Context));