Spelling mistakes in comments. NFCI. (PR27635)

llvm-svn: 299083
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 224dec1..0fa467f 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -987,7 +987,7 @@
 void StringLiteral::setString(const ASTContext &C, StringRef Str,
                               StringKind Kind, bool IsPascal) {
   //FIXME: we assume that the string data comes from a target that uses the same
-  // code unit size and endianess for the type of string.
+  // code unit size and endianness for the type of string.
   this->Kind = Kind;
   this->IsPascal = IsPascal;