Need the definite article

Co-authored-by: brandon s allbery kf8nh <[email protected]>

Author: philderbeast

doc/cabal-package-description-file.rst

@@ -3040,7 +3040,7 @@ with a listing in :pkg-field:`other-modules` or
 
    A list of autogenerated modules. Each one of these modules must also be
    listed elsewhere as if they were modules on disk.  Autogenerated modules are
-   not packaged by ``cabal sdist`` command.
+   not packaged by the ``cabal sdist`` command.
 
 ::