postgresql_user: fix documentation formatting (#1219)

* postgresql_user: fix documentation formatting

* fix

plugins/modules/database/postgresql/postgresql_user.py

@@ -38,8 +38,8 @@ options:
       plain text format.
     - When passing an MD5-hashed password, you must generate it with the format
       C('str["md5"] + md5[ password + username ]'), resulting in a total of
-      35 characters. An easy way to do this is C(echo "md5$(echo -n
-      'verysecretpasswordJOE' | md5sum | awk '{print $1}')").
+      35 characters. An easy way to do this is
+      C(echo "md5`echo -n 'verysecretpasswordJOE' | md5sum | awk '{print $1}'`").
     - Note that if the provided password string is already in MD5-hashed
       format, then it is used as-is, regardless of I(encrypted) option.
     type: str