Correct a couple of unbalanced parenthesis. (GH-10779)

diff --git a/Doc/c-api/buffer.rst b/Doc/c-api/buffer.rst
index 5a9a46f..33abb5b 100644
--- a/Doc/c-api/buffer.rst
+++ b/Doc/c-api/buffer.rst
@@ -198,7 +198,7 @@
       indicates that no de-referencing should occur (striding in a contiguous
       memory block).
 
-      If all suboffsets are negative (i.e. no de-referencing is needed, then
+      If all suboffsets are negative (i.e. no de-referencing is needed), then
       this field must be NULL (the default value).
 
       This type of array representation is used by the Python Imaging Library