add missing word

Author: tbrowder

doc/Language/phasers.pod6

@@ -451,7 +451,7 @@ Appears in a supply block. Called when the supply is closed.
 =head2 X<DOC|Asynchronous Phasers, DOC>
 
 The phasers C<BEGIN>, C<CHECK> and C<INIT> are run only in documentation mode
-when prefixed with the C<DOC> keyword. The compiler is in documentation when run
+when prefixed with the C<DOC> keyword. The compiler is in documentation mode when run
 with C<--doc>.
 
   DOC INIT { say 'init'  }  # prints 'init' at initialization time when in documentation mode.