MXS-1220: Remove redundant parameter documentation

As all requests support the only parameter `pretty`, there's no point in
documenting it separately for each resource.

Documentation/REST-API/Resources-User.md

@@ -33,10 +33,6 @@ GET /v1/users/inet/:name
 }
 ```
 
-#### Supported Request Parameter
-
-- `pretty`
-
 ### Get all network users
 
 Get all network users.
@@ -66,10 +62,6 @@ GET /v1/users/inet
 }
 ```
 
-#### Supported Request Parameter
-
-- `pretty`
-
 ### Get enabled UNIX account
 
 Get a single enabled UNIX account. The The _:name_ in the URI must be a valid
@@ -100,10 +92,6 @@ GET /v1/users/unix/:name
 }
 ```
 
-#### Supported Request Parameter
-
-- `pretty`
-
 ### Get all enabled UNIX accounts
 
 Get all enabled UNIX accounts.
@@ -133,10 +121,6 @@ GET /v1/users/unix
 }
 ```
 
-#### Supported Request Parameter
-
-- `pretty`
-
 ### Get all users
 
 Get all administrative users. This fetches both network users and local UNIX
@@ -174,10 +158,6 @@ GET /v1/users
 }
 ```
 
-#### Supported Request Parameter
-
-- `pretty`
-
 ### Create a network user
 
 Create a new network user.