Added select support.

scrbl/wv-window.scrbl

@@ -133,6 +133,7 @@ following classes is instantiated:
  @item{@racket[wv-input/check%] for @racket['checkbox]}
  @item{@racket[wv-input/radio%] for @racket['radio]}
  @item{@racket[wv-input/color%] for @racket['color]}
+ @item{@racket[wv-input/select%] for an HTML @tt{select} element}
  @item{@racket[wv-element%] otherwise}]
 
 Newly created wrappers receive this window through the @racket[window] init
@@ -537,4 +538,4 @@ This module also re-exports the public APIs from:
  @item{@racketmodname[rgba]}
  @item{@racketmodname[wv-settings]}]
 
-It also re-exports @racket[webview-version].
+It also re-exports @racket[webview-version].