[Python-checkins] Minor C API documentation improvements. (GH-17698)

[Benjamin Peterson]

https://github.com/python/cpython/commit/090bc148834aa4c92c683c2c07be572c31dd1b68
commit: 090bc148834aa4c92c683c2c07be572c31dd1b68
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Benjamin Peterson <benjamin at python.org>
date: 2019-12-24T22:35:20-06:00
summary:

Minor C API documentation improvements. (GH-17698)

The added parentheses around the PyIter_Next assignment suppress the following warning which gcc throws without:
```
warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
```
The other change is a typo fix
(cherry picked from commit 5c7ed7550ec2da16d7679e538fcd7c1a5631811f)

Co-authored-by: William Ayd <william.ayd at icloud.com>

files:
M Doc/c-api/iter.rst
M Doc/includes/custom.c

diff --git a/Doc/c-api/iter.rst b/Doc/c-api/iter.rst
index 62ca082713b68..6507da9c7f0a5 100644
--- a/Doc/c-api/iter.rst
+++ b/Doc/c-api/iter.rst
@@ -29,7 +29,7 @@ something like this::
        /* propagate error */
    }
 
-   while (item = PyIter_Next(iterator)) {
+   while ((item = PyIter_Next(iterator))) {
        /* do something with item */
        ...
        /* release reference when done */
diff --git a/Doc/includes/custom.c b/Doc/includes/custom.c
index bda32e2ad81d4..f361baf830dd1 100644
--- a/Doc/includes/custom.c
+++ b/Doc/includes/custom.c
@@ -37,7 +37,7 @@ PyInit_custom(void)
     Py_INCREF(&CustomType);
     if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
         Py_DECREF(&CustomType);
-        PY_DECREF(m);
+        Py_DECREF(m);
         return NULL;
     }