Move igzip_lib documentation

Author: rhpvorderman

docs/index.rst

@@ -107,13 +107,6 @@ Differences with zlib and gzip modules
    :start-after: .. differences start
    :end-before: .. differences end
 
-============================
-API Documentation: igzip_lib
-============================
-
-.. automodule:: isal.igzip_lib
-   :members:
-
 ============================
 API Documentation: isal_zlib
 ============================
@@ -132,6 +125,13 @@ API-documentation: igzip
       :members:
       :special-members: __init__
 
+============================
+API Documentation: igzip_lib
+============================
+
+.. automodule:: isal.igzip_lib
+   :members:
+
 ==========================
 python -m isal.igzip usage
 ==========================