bpo-31678: Fix typo in PyDateTime_DELTA_GET_MICROSECONDS (GH-3869)

diff --git a/Doc/c-api/datetime.rst b/Doc/c-api/datetime.rst
index 39542bd..305e990 100644
--- a/Doc/c-api/datetime.rst
+++ b/Doc/c-api/datetime.rst
@@ -188,7 +188,7 @@
    .. versionadded:: 3.3
 
 
-.. c:function:: int PyDateTime_DELTA_GET_MICROSECOND(PyDateTime_Delta *o)
+.. c:function:: int PyDateTime_DELTA_GET_MICROSECONDS(PyDateTime_Delta *o)
 
    Return the number of microseconds, as an int from 0 through 999999.