[docs] Remove stale dependencies when running gclient. (#33410)
[docs] Remove stale dependencies when running gclient. (#33410)

Add a reference to the -D argument to `gclient sync`.
rmacnak-google/engine,rmacnak-google/engine,flutter/engine,devoncarew/engine,chinmaygarde/flutter_engine,rmacnak-google/engine,rmacnak-google/engine,chinmaygarde/flutter_engine,devoncarew/engine,chinmaygarde/flutter_engine,rmacnak-google/engine,chinmaygarde/flutter_engine,devoncarew/engine,flutter/engine,flutter/engine,chinmaygarde/flutter_engine,flutter/engine,flutter/engine,chinmaygarde/flutter_engine,rmacnak-google/engine,devoncarew/engine,devoncarew/engine,flutter/engine,flutter/engine,flutter/engine,devoncarew/engine,rmacnak-google/engine,chinmaygarde/flutter_engine,devoncarew/engine