Avoid analyzing excluded language files for line counting

This change passes in a list of file types to the line counting
analysis. These are the languages for the databases being analyzed.
Line count analysis is restricted to these files.

node_modules/github-linguist/dist/directory.d.ts

@@ -3,6 +3,7 @@ export interface LocDirOptions {
     cwd?: string;
     include?: string[] | string;
     exclude?: string[] | string;
+    analysisLanguages?: string[];
 }
 export interface LocResult {
     files: string[];
@@ -20,9 +21,16 @@ export declare class LocDir {
     private cwd;
     private include;
     private exclude;
+    private analysisLanguages?;
+    private allLanguages;
     constructor(options: LocDirOptions);
     /**
      * Calculate directory info.
      */
     loadInfo(): Promise<LocResult>;
+    /**
+     * Ignore analyzing this file if analysis languages are specified
+     * and this language is not one of them.
+     */
+    private ignoreLanguage;
 }