Fixes gh-21 Function grant//create doc improvments

Author: pgulutzan

sphinx/book/box/authentication.rst

@@ -280,8 +280,8 @@ The possible options are:
 
     box.schema.func.create('f', {language = 'C', setuid = false})
 
-Specifying :code:`if_not_exists=true` would cause ``error: Function '...' already
-exists`` if the function already exists.
+Specifying :code:`if_not_exists=false` would cause ``error: Function '...' already
+exists`` if the _func tuple already exists.
 
 Specifying :code:`setuid=true` would cause the setuid flag (the fourth field in
 the _func tuple) to have a value meaning "true", and the effect of that is that

sphinx/book/box/box_schema.rst

@@ -144,12 +144,14 @@ available for insert, select, and all the other :ref:`box.space <box_space>` fun
     Grant :ref:`privileges <authentication-privileges>` to a user.
 
     :param string user-name: the name of the user
-    :param string privileges: either privilege,object-type,object-name
-                              or privilege,'universe' where privilege =
-                              'read' or 'write' or 'execute' or a combination
+    :param string privileges: privilege,object-type,object-name
+                              where privilege = 'read' or 'write' or 'execute' or a combination,
                               and object-type = 'space' or 'function'.
+                              Or: privilege,'universe'.
                               Or: role-name.
 
+    If :samp:`'function','{object-name}'` is specified, then a _func tuple with that object-name must exist.
+
     **Examples:**
 
         box.schema.user.grant('Lena', 'read', 'space', 'tester') |br|
@@ -162,10 +164,10 @@ available for insert, select, and all the other :ref:`box.space <box_space>` fun
     Revoke :ref:`privileges <authentication-privileges>` from a user.
 
     :param string user-name: the name of the user
-    :param string privileges: either privilege,object-type,object-name
-                              or privilege,'universe' where privilege =
-                              'read' or 'write' or 'execute' or a combination
+    :param string privileges: privilege,object-type,object-name
+                              where privilege = 'read' or 'write' or 'execute' or a combination,
                               and object-type = 'space' or 'function'.
+                              Or: privilege,'universe'.
                               Or: role-name.
 
     **Examples:**