fix: Links to localhost addresses (#1505)

Co-authored-by: Lucas Costi <[email protected]>

Author: nschonni

content/developers/apps/authorizing-oauth-apps.md

@@ -272,7 +272,9 @@ The optional `redirect_uri` parameter can also be used for localhost URLs. If th
 
 For the `http://localhost/path` callback URL, you can use this `redirect_uri`:
 
-   http://localhost:1234/path
+```
+http://localhost:1234/path
+```
 
 ### Creating multiple tokens for OAuth Apps
 

content/developers/apps/using-content-attachments.md

@@ -166,7 +166,7 @@ To create a Probot App, follow these steps:
     }
     ```
 
-4. [Run the GitHub App locally](https://probot.github.io/docs/development/#running-the-app-locally). Navigate to [localhost:3000](http://localhost:3000), and click the **Register GitHub App** button:
+4. [Run the GitHub App locally](https://probot.github.io/docs/development/#running-the-app-locally). Navigate to `http://localhost:3000`, and click the **Register GitHub App** button:
 
    ![Register a Probot GitHub App](/assets/images/github-apps/github_apps_probot-registration.png)
 

lib/excluded-links.js

@@ -9,10 +9,6 @@ module.exports = [
   'https://github.com/github/docs/edit',
   'https://github.com/github/insights-releases/releases/latest',
 
-  // Developer content uses these for examples; they should not be checked.
-  'http://localhost:1234',
-  'localhost:3000',
-
   // Oneoff links that link checkers think are broken but are not.
   'https://haveibeenpwned.com/',
   'https://www.ilo.org/dyn/normlex/en/f\\?p=NORMLEXPUB:12100:0::NO::P12100_ILO_CODE:P029'