Add useful information to MRVA gist titles

All exported MRVA gists are given the name `CodeQL variant analysis
results', which makes it hard to work out what it contains at a glance.

We're adding more information in the gist title to make it more useful.

Example of new title:

`Empty Block (Go) x results (y repositories)`

This translates to:

`<query name> (<query language>) <number of results> results (<number of repositories> repositories)`

Co-authored-by: Shati Patel <shati-patel@github.com>

extensions/ql-vscode/src/remote-queries/export-results.ts

@@ -80,7 +80,7 @@ async function exportResultsToGist(
   analysesResults: AnalysisResults[]
 ): Promise<void> {
   const credentials = await Credentials.initialize(ctx);
-  const description = 'CodeQL Variant Analysis Results';
+  const description = buildGistDescription(query, analysesResults);
   const markdownFiles = generateMarkdown(query, analysesResults, 'gist');
   // Convert markdownFiles to the appropriate format for uploading to gist
   const gistFiles = markdownFiles.reduce((acc, cur) => {
@@ -100,6 +100,15 @@ async function exportResultsToGist(
   }
 }
 
+/**
+ * Builds Gist description
+ * Ex: Empty Block (Go) x results (y repositories)
+ */
+const buildGistDescription = (query: RemoteQuery, analysesResults: AnalysisResults[]) => {
+  const resultCount = sumAnalysesResults(analysesResults);
+  return `${query.queryName} (${query.language}) ${resultCount} results (${query.numRepositoriesQueried} repositories)`;
+};
+
 /**
  * Converts the results of a remote query to markdown and saves the files locally
  * in the query directory (where query results and metadata are also saved).