Update postgresql_user.py (#45146)

* Update postgresql_user.py

md5sum generates output with hypen. Something like the following
```
$ echo "md5$(echo -n 'verysecretpasswordJOE' | md5sum)"
md5d011966da94d776cf59bf6dbde240e5d  -
```

We need to remove hyphen from the output. Also the command by itself is incorrect

```
echo "md5$(echo -n 'verysecretpasswordJOE' | md5sum")
```

double quotes must be after right parenthesis

```
echo "md5$(echo -n 'verysecretpasswordJOE' | md5sum)"
```

+label: docsite_pr

* Update postgresql_user.py

Add curly braces

lib/ansible/modules/database/postgresql/postgresql_user.py

@@ -48,7 +48,7 @@ options:
       - When passing a hashed password it must be generated 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)").
+        '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 C(encrypted) parameter.
   db: