Add a new warning gategory, ResourceWarning, as discussed on python-dev. It is silent by default,
except when configured --with-pydebug.
Emit this warning from the GC shutdown procedure, rather than just printing to stderr.
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index 309fec5..64689ad 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -82,6 +82,9 @@
| :exc:`BytesWarning` | Base category for warnings related to |
| | :class:`bytes` and :class:`buffer`. |
+----------------------------------+-----------------------------------------------+
+| :exc:`ResourceWarning` | Base category for warnings related to |
+| | resource usage. |
++----------------------------------+-----------------------------------------------+
While these are technically built-in exceptions, they are documented here,