fixed docs on the meaning of -H sudo arg

fixes #7418

docsite/rst/intro_configuration.rst

@@ -524,7 +524,7 @@ the sudo implementation is matching CLI flags with the standard sudo::
 sudo_flags
 ==========
 
-Additional flags to pass to sudo when engaging sudo support.  The default is '-H' which preserves the environment
+Additional flags to pass to sudo when engaging sudo support.  The default is '-H' which preserves the $HOME environment variable
 of the original user.  In some situations you may wish to add or remove flags, but in general most users
 will not need to change this setting::