docs(api) Fix url (#5367)

A little slash had been missing since eddb23b

docs/api.md

@@ -532,7 +532,7 @@ try {
   - `product` <[string]> Which browser to launch. At this time, this is either `chrome` or `firefox`. See also `PUPPETEER_PRODUCT`.
   - `ignoreHTTPSErrors` <[boolean]> Whether to ignore HTTPS errors during navigation. Defaults to `false`.
   - `headless` <[boolean]> Whether to run browser in [headless mode](https://developers.google.com/web/updates/2017/04/headless-chrome). Defaults to `true` unless the `devtools` option is `true`.
-  - `executablePath` <[string]> Path to a browser executable to run instead of the bundled Chromium. If `executablePath` is a relative path, then it is resolved relative to [current working directory](https://nodejs.org/api/process.html#process_process_cwd). **BEWARE**: Puppeteer is only [guaranteed to work](https://github.compuppeteer/puppeteer/#q-why-doesnt-puppeteer-vxxx-work-with-chromium-vyyy) with the bundled Chromium, use at your own risk.
+  - `executablePath` <[string]> Path to a browser executable to run instead of the bundled Chromium. If `executablePath` is a relative path, then it is resolved relative to [current working directory](https://nodejs.org/api/process.html#process_process_cwd). **BEWARE**: Puppeteer is only [guaranteed to work](https://github.com/puppeteer/puppeteer/#q-why-doesnt-puppeteer-vxxx-work-with-chromium-vyyy) with the bundled Chromium, use at your own risk.
   - `slowMo` <[number]> Slows down Puppeteer operations by the specified amount of milliseconds. Useful so that you can see what is going on.
   - `defaultViewport` <?[Object]> Sets a consistent viewport for each page. Defaults to an 800x600 viewport. `null` disables the default viewport.
     - `width` <[number]> page width in pixels.