Update by comments

Fix comments recieved from SME

Author: AArdeev

doc/reference/reference_lua/box_error.rst

@@ -277,7 +277,7 @@ Below is a list of ``box.error`` functions and related objects.
             - Set the specified error as the last system error explicitly
 
         *   - :doc:`./box_error/is`
-            - Verify whether the specified argument is an error
+            - Verify whether the specified argument is an error cdata object
 
         *   - :doc:`./box_error/error_object`
             - An object that defines an error

doc/reference/reference_lua/box_error/error_object.rst

@@ -196,6 +196,6 @@ error_object
 
         **Since:** :doc:`3.1.0 </release/3.1.0>`
 
-        Returns the name of the error used at creation.
+        Returns the name of the error.
 
 

doc/reference/reference_lua/box_error/is.rst

@@ -4,25 +4,26 @@
 box.error.is()
 ===============================================================================
 
-.. function:: box.error.is(object_name)
+.. function:: box.error.is(object)
 
     **Since:** :doc:`3.2.0 </release/3.2.0>`
 
-    The ``box.error.is`` function allows verify whether the specified argument is an error.
+    The ``box.error.is`` function allows verify whether the specified argument is an error cdata object.
 
-    :param object_name object_name: the subject of the request
+    :param object object: the name of the othe object to be verified.
 
     **Return type:**
     boolean
 
     **Example**
 
-        ..  code-block:: lua
-            tarantool> box.error.is(box.error.new(box.error.UNKNOWN))
-            ---
-            - true
-            ...
-            tarantool> box.error.is('foo')
-            ---
-            - false
-            ...
+    ..  code-block:: lua
+
+        tarantool> box.error.is(box.error.new(box.error.UNKNOWN))
+        ---
+        - true
+        ...
+        tarantool> box.error.is('foo')
+        ---
+        - false
+        ...