[babel] fix typo in doc

required/babel/babel.dtx

@@ -730,7 +730,7 @@ shorthands such as |!| are used to insert the right amount of white
 space; (3) several kinds of discretionaries and breaks can be inserted
 easily with |"-|, |"=|, etc.
 
-The package \textsf{inputenc} as well as \xetex{} an \luatex{} have
+The package \textsf{inputenc} as well as \xetex{} and \luatex{} have
 alleviated entering non-ASCII characters, but minority languages and
 some kinds of text can still require characters not directly available
 on the keyboards (and sometimes not even as separated or precomposed