Bug 1619956 : Added link to documentation without adding a new command. r=sylvestre

Differential Revision: https://phabricator.services.mozilla.com/D65934

--HG--
extra : moz-landing-system : lando

python/mozbuild/mozbuild/code-analysis/mach_commands.py

@@ -179,6 +179,9 @@ class StaticAnalysis(MachCommandBase):
              description='Run C++ static analysis checks')
     def static_analysis(self):
         # If no arguments are provided, just print a help message.
+        """Detailed documentation:
+        https://firefox-source-docs.mozilla.org/code-quality/static-analysis.html
+        """
         mach = Mach(os.getcwd())
 
         def populate_context(context, key=None):