Split the monstrous C API manual files in smaller parts.
diff --git a/Doc/c-api/objimpl.rst b/Doc/c-api/objimpl.rst
new file mode 100644
index 0000000..b335188
--- /dev/null
+++ b/Doc/c-api/objimpl.rst
@@ -0,0 +1,18 @@
+.. highlightlang:: c
+
+
+.. _newtypes:
+
+*****************************
+Object Implementation Support
+*****************************
+
+This chapter describes the functions, types, and macros used when defining new
+object types.
+
+.. toctree::
+
+ allocation.rst
+ structures.rst
+ typeobj.rst
+ gcsupport.rst