Bug 1885890 - Increase the warning limit on docs/config.yml after firefox-android was added into mc r=ahal

Differential Revision: https://phabricator.services.mozilla.com/D204935

docs/config.yml

@@ -123,4 +123,4 @@ fatal warnings:
     - "WARNING: '([^']*)' reference target not found:((?!.rst).)*$"
     - "WARNING: Include file '([^']*)' not found or reading it failed"
 
-max_num_warnings: 759
+max_num_warnings: 835