doc: flesh out description of ":eval" header argument

  Thanks to Stephen Eglen for this patch

doc/org.texi

@@ -12990,10 +12990,10 @@ permissions of the tangled file are set to make it executable.
 @subsubsection @code{:eval}
 The @code{:eval} header argument can be used to limit the evaluation of
 specific code blocks.  @code{:eval} accepts two arguments ``never'' and
-``query''.  @code{:eval never} will ensure that a code block is never
-evaluated, this can be useful for protecting against the evaluation of
-dangerous code blocks.  @code{:eval query} will require a query for every
-execution of a code block regardless of the value of the
+``query''.  @code{:eval never} (or @code{:eval no}) will ensure that a code
+block is never evaluated, this can be useful for protecting against the
+evaluation of dangerous code blocks.  @code{:eval query} will require a query
+for every execution of a code block regardless of the value of the
 @code{org-confirm-babel-evaluate} variable.
 
 If this header argument is not set then evaluation is determined by the value