fix a bunch of comment typos found by codespell.  Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129559
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index d53da9f..fa86f05 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1791,7 +1791,7 @@
   LValue EmitComplexAssignmentLValue(const BinaryOperator *E);
   LValue EmitComplexCompoundAssignmentLValue(const CompoundAssignOperator *E);
 
-  // Note: only availabe for agg return types
+  // Note: only available for agg return types
   LValue EmitBinaryOperatorLValue(const BinaryOperator *E);
   LValue EmitCompoundAssignmentLValue(const CompoundAssignOperator *E);
   // Note: only available for agg return types