bpo-20408: Fix memoryview() signature in docs (GH-24431)

(cherry picked from commit d18e5dae914b1db49b25ed7729c07a535d1f0c52)

Co-authored-by: Mariusz Felisiak <felisiak.mariusz@gmail.com>
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 7d8a669..bc55d42 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1022,7 +1022,7 @@
 
 
 .. _func-memoryview:
-.. class:: memoryview(obj)
+.. class:: memoryview(object)
    :noindex:
 
    Return a "memory view" object created from the given argument.  See