[NFC][VFS] Fix typos in comments.

llvm-svn: 339215
diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index c0dc619..1af4a11 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -990,7 +990,7 @@
 ///   'type': 'file',
 ///   'name': <string>,
 ///   'use-external-name': <boolean> # Optional
-///   'external-contents': <path to external file>)
+///   'external-contents': <path to external file>
 /// }
 /// \endverbatim
 ///
@@ -1021,7 +1021,7 @@
   /// Currently, case-insensitive matching only works correctly with ASCII.
   bool CaseSensitive = true;
 
-  /// IsRelativeOverlay marks whether a IsExternalContentsPrefixDir path must
+  /// IsRelativeOverlay marks whether a ExternalContentsPrefixDir path must
   /// be prefixed in every 'external-contents' when reading from YAML files.
   bool IsRelativeOverlay = false;