JS: Rename Diagnostics folder to Summary

javascript/ql/src/Summary/LinesOfCode.ql

@@ -0,0 +1,11 @@
+/**
+ * @id js/summary/lines-of-code
+ * @name Total lines of JavaScript and TypeScript code in the database
+ * @description The total number of lines of JavaScript or TypeScript code across all files checked into the repository, except in `node_modules`. This is a useful metric of the size of a database. For all files that were seen during extraction, this query counts the lines of code, excluding whitespace or comments.
+ * @kind metric
+ * @tags summary
+ */
+
+import javascript
+
+select sum(File f | not f.getATopLevel().isExterns() | f.getNumberOfLinesOfCode())