Issue #25523: Backported a-to-an corrections.
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
index 192bd4d..70e1483 100644
--- a/Doc/library/zlib.rst
+++ b/Doc/library/zlib.rst
@@ -31,7 +31,7 @@
.. function:: adler32(data[, value])
- Computes a Adler-32 checksum of *data*. (An Adler-32 checksum is almost as
+ Computes an Adler-32 checksum of *data*. (An Adler-32 checksum is almost as
reliable as a CRC32 but can be computed much more quickly.) If *value* is
present, it is used as the starting value of the checksum; otherwise, a fixed
default value is used. This allows computing a running checksum over the