bpo-45463: Clarify that global statements allows multiple names (pyth…

…onGH-28851)

The global statement allows specifying a list of identifiers
(https://docs.python.org/3/reference/simple_stmts.html#the-global-statement).

The "Execution model" chapter described the global statement as if it
only allowed one single name. Pluralize "name" in the appropriate places.

Doc/reference/executionmodel.rst

@@ -119,14 +119,14 @@ is subtle.  Python lacks declarations and allows name binding operations to
 occur anywhere within a code block.  The local variables of a code block can be
 determined by scanning the entire text of the block for name binding operations.
 
-If the :keyword:`global` statement occurs within a block, all uses of the name
-specified in the statement refer to the binding of that name in the top-level
+If the :keyword:`global` statement occurs within a block, all uses of the names
+specified in the statement refer to the bindings of those names in the top-level
 namespace.  Names are resolved in the top-level namespace by searching the
 global namespace, i.e. the namespace of the module containing the code block,
 and the builtins namespace, the namespace of the module :mod:`builtins`.  The
-global namespace is searched first.  If the name is not found there, the
+global namespace is searched first.  If the names are not found there, the
 builtins namespace is searched.  The :keyword:`!global` statement must precede
-all uses of the name.
+all uses of the listed names.
 
 The :keyword:`global` statement has the same scope as a name binding operation
 in the same block.  If the nearest enclosing scope for a free variable contains