[clang] [NFC] Fix a couple of typos: assuments and assingment

clang/lib/Sema/CheckExprLifetime.cpp

@@ -472,7 +472,7 @@ shouldTrackFirstArgumentForConstructor(const CXXConstructExpr *Ctor) {
 }
 
 // Return true if this is an "normal" assignment operator.
-// We assuments that a normal assingment operator always returns *this, that is,
+// We assume that a normal assignment operator always returns *this, that is,
 // an lvalue reference that is the same type as the implicit object parameter
 // (or the LHS for a non-member operator$=).
 static bool isNormalAssignmentOperator(const FunctionDecl *FD) {