fix: allow code generation from typescript generic graphql tag

Allow to use generic graph tag like: graphql<TResponse>`{ myQuery }`

Author: hugo082

packages/apollo-language-server/src/__tests__/document.test.ts

@@ -93,6 +93,33 @@ describe("extractGraphQLDocuments", () => {
       expect(documents[0].syntaxErrors.length).toBe(0);
       expect(documents[0].ast.definitions.length).toBe(2);
     });
+
+    it("works with a generic tagname", () => {
+      const textDocument = mockTextDocument(`
+      gql <TResponse, TOther> \`
+        {
+          hero {
+            ...Hero_character
+          }
+        }
+
+        \${Hero.fragments.character}
+
+        {
+          reviews(episode: NEWHOPE) {
+            ...ReviewList_reviews
+          }
+        }
+
+        \${ReviewList.fragments.reviews}
+      \`
+    `);
+      const documents = extractGraphQLDocuments(textDocument);
+
+      expect(documents.length).toEqual(1);
+      expect(documents[0].syntaxErrors.length).toBe(0);
+      expect(documents[0].ast.definitions.length).toBe(2);
+    });
   });
 
   describe("extracting documents from ReasonML extension nodes", () => {

packages/apollo-language-server/src/document.ts

@@ -89,11 +89,11 @@ function extractGraphQLDocumentsFromJSTemplateLiterals(
 
   const documents: GraphQLDocument[] = [];
 
-  const regExp = new RegExp(`${tagName}\\s*\`([\\s\\S]+?)\``, "gm");
+  const regExp = new RegExp(`${tagName}\\s*(?:<([\\sa-zA-Z0-9_,<>]+)>)?\\s*\`([\\s\\S]+?)\``, "gm");
 
   let result;
   while ((result = regExp.exec(text)) !== null) {
-    const contents = replacePlaceholdersWithWhiteSpace(result[1]);
+    const contents = replacePlaceholdersWithWhiteSpace(result[2]);
     const position = document.positionAt(result.index + (tagName.length + 1));
     const locationOffset: SourceLocation = {
       line: position.line + 1,