Clean up as many of the comments in Basic I can find to talk in terms of
'expansion' rather than 'instantiation' for macro source locations.

llvm-svn: 136058
diff --git a/clang/lib/Basic/SourceLocation.cpp b/clang/lib/Basic/SourceLocation.cpp
index a13bbc5..6e4f3e6 100644
--- a/clang/lib/Basic/SourceLocation.cpp
+++ b/clang/lib/Basic/SourceLocation.cpp
@@ -48,7 +48,7 @@
       OS << "<invalid>";
       return;
     }
-    // The instantiation and spelling pos is identical for file locs.
+    // The macro expansion and spelling pos is identical for file locs.
     OS << PLoc.getFilename() << ':' << PLoc.getLine()
        << ':' << PLoc.getColumn();
     return;