Add fourslash test of jsdoc backtick parsing

Author: sandersn

tests/cases/fourslash/quickInfoJSDocBackticks.ts

@@ -0,0 +1,25 @@
+///<reference path="fourslash.ts" />
+
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @strict: true
+// @Filename: jsdocParseMatchingBackticks.js
+
+/////**
+//// * `@param` initial at-param is OK in title comment
+//// * @param {string} x hi there `@param`
+//// * @param {string} y hi there `@ * param
+//// *                   this is the margin
+//// */
+////export function f(x, y) {
+////    return x/*x*/ + y/*y*/
+////}
+////f/*f*/
+
+goTo.marker("f");
+verify.quickInfoIs("function f(x: string, y: string): string", "`@param` initial at-param is OK in title comment");
+goTo.marker("x");
+verify.quickInfoIs("(parameter) x: string", "hi there `@param`");
+goTo.marker("y");
+verify.quickInfoIs("(parameter) y: string", "hi there `@ * param\nthis is the margin");