fix: make selectionStart/End nullable

Author: XiNiHa

src/Webapi/Dom/Webapi__Dom__HtmlInputElement.res

@@ -81,10 +81,10 @@ module Impl = (
   @set external setMin: (t_htmlInputElement, string) => unit = "min"
   @get external max: t_htmlInputElement => string = "max"
   @set external setMax: (t_htmlInputElement, string) => unit = "max"
-  @get external selectionStart: t_htmlInputElement => int = "selectionStart"
-  @set external setSelectionStart: (t_htmlInputElement, int) => unit = "selectionStart"
-  @get external selectionEnd: t_htmlInputElement => int = "selectionEnd"
-  @set external setSelectionEnd: (t_htmlInputElement, int) => unit = "selectionEnd"
+  @get @return(nullable) external selectionStart: t_htmlInputElement => option<int> = "selectionStart"
+  @set external setSelectionStart: (t_htmlInputElement, option<int>) => unit = "selectionStart"
+  @get @return(nullable) external selectionEnd: t_htmlInputElement => option<int> = "selectionEnd"
+  @set external setSelectionEnd: (t_htmlInputElement, option<int>) => unit = "selectionEnd"
   @get external selectionDirection: t_htmlInputElement => string = "selectionDirection"
   @set
   external setSelectionDirection: (t_htmlInputElement, string) => unit = "selectionDirection"

src/Webapi/Dom/Webapi__Dom__HtmlTextAreaElement.res

@@ -79,10 +79,10 @@ external form: t => option<Dom.htmlFormElement> = "form"
 type selectionDirection = [#forward | #backward | #none]
 
 @send external select: t => unit = "select"
-@get external selectionStart: t => int = "selectionStart"
-@set external setSelectionStart: (t, int) => unit = "selectionStart"
-@get external selectionEnd: t => int = "selectionEnd"
-@set external setSelectionEnd: (t, int) => unit = "selectionEnd"
+@get @return(nullable) external selectionStart: t => option<int> = "selectionStart"
+@set external setSelectionStart: (t, option<int>) => unit = "selectionStart"
+@get @return(nullable) external selectionEnd: t => option<int> = "selectionEnd"
+@set external setSelectionEnd: (t, option<int>) => unit = "selectionEnd"
 @get
 external selectionDirection: t => selectionDirection = "selectionDirection"
 @set