Corrected MacOS get_pref_path() documentation

The path generated by get_pref_path should have included the "prg" parameter.  (In the example, this has the value of "My Company")

Author: IrvKalb

docs/reST/ref/system.rst

@@ -41,7 +41,7 @@ open just in case something obvious comes up.
         C:\\Users\\bob\\AppData\\Roaming\\My Company\\My Program Name\\
 
         On macOS, it would resemble
-        /Users/bob/Library/Application Support/My Program Name/
+        /Users/bob/Library/Application Support/My Company/My Program Name/
 
         And on Linux it would resemble
         /home/bob/.local/share/My Program Name/