bpo-36974: expand call protocol documentation (GH-13844)



CC @encukou 

I'm also adding Petr Viktorin as contributor for vectorcall in the "what's new" section.


https://bugs.python.org/issue36974



Automerge-Triggered-By: @encukou

Automerge-Triggered-By: @encukou
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
index cd6df00..2edcbf7 100644
--- a/Doc/c-api/exceptions.rst
+++ b/Doc/c-api/exceptions.rst
@@ -697,6 +697,8 @@
    ``0`` on success, ``-1`` on failure.
 
 
+.. _recursion:
+
 Recursion Control
 =================
 
@@ -704,6 +706,8 @@
 level, both in the core and in extension modules.  They are needed if the
 recursive code does not necessarily invoke Python code (which tracks its
 recursion depth automatically).
+They are also not needed for *tp_call* implementations
+because the :ref:`call protocol <call>` takes care of recursion handling.
 
 .. c:function:: int Py_EnterRecursiveCall(const char *where)