Fixed links

docs/en/manuals/extensions-cocoapods.md

@@ -23,5 +23,5 @@ The build server will collect the `Podfile` files from all the extensions and us
 
 Examples:
 
-* https://github.com/defold/extension-firebase/blob/master/firebase/manifests/ios/Podfile
-* https://github.com/defold/extension-facebook/blob/master/facebook/manifests/ios/Podfile
+* [Firebase](https://github.com/defold/extension-firebase/blob/master/firebase/manifests/ios/Podfile)
+* [Facebook](https://github.com/defold/extension-facebook/blob/master/facebook/manifests/ios/Podfile)

docs/en/manuals/extensions-gradle.md

@@ -27,5 +27,5 @@ The build server will collect the `build.gradle` files from all the extensions a
 
 Examples:
 
-* https://github.com/defold/extension-firebase/blob/master/firebase/manifests/android/build.gradle
-* https://github.com/defold/extension-facebook/blob/master/facebook/manifests/android/build.gradle
+* [Firebase](https://github.com/defold/extension-firebase/blob/master/firebase/manifests/android/)build.gradle
+* [Facebook](https://github.com/defold/extension-facebook/blob/master/facebook/manifests/android/build.gradle)