fix instances of consecutive articles (closes #23221)

Patch by Karan Goel.
diff --git a/Doc/distutils/apiref.rst b/Doc/distutils/apiref.rst
index 2a75a46..8366d8a 100644
--- a/Doc/distutils/apiref.rst
+++ b/Doc/distutils/apiref.rst
@@ -970,7 +970,7 @@
 .. function:: create_tree(base_dir, files[, mode=0777, verbose=0, dry_run=0])
 
    Create all the empty directories under *base_dir* needed to put *files* there.
-   *base_dir* is just the a name of a directory which doesn't necessarily exist
+   *base_dir* is just the name of a directory which doesn't necessarily exist
    yet; *files* is a list of filenames to be interpreted relative to *base_dir*.
    *base_dir* + the directory portion of every file in *files* will be created if
    it doesn't already exist.  *mode*, *verbose* and *dry_run* flags  are as for