Issue #25523: Correct "a" article to "an" article
This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
to fix the grammar.
diff --git a/Modules/audioop.c b/Modules/audioop.c
index e829e4d..a4d1375 100644
--- a/Modules/audioop.c
+++ b/Modules/audioop.c
@@ -121,7 +121,7 @@
/*
* linear2ulaw() accepts a 14-bit signed integer and encodes it as u-law data
- * stored in a unsigned char. This function should only be called with
+ * stored in an unsigned char. This function should only be called with
* the data shifted such that it only contains information in the lower
* 14-bits.
*