Added ReactTagOf type alias and changelog entry

Author: oyvindberg

core/src/main/scala/japgolly/scalajs/react/vdom/package.scala

@@ -19,8 +19,10 @@ package object vdom {
 
   // If you're wondering why abstract class instead of trait, https://issues.scala-lang.org/browse/SI-4767
   abstract class Base extends Implicits {
-    final type ReactTag = japgolly.scalajs.react.vdom.ReactTagOf[TopNode]
-    final type TagMod   = japgolly.scalajs.react.vdom.TagMod
+    final type ReactTagOf[+N <: TopNode] = japgolly.scalajs.react.vdom.ReactTagOf[N]
+    final type ReactTag                  = japgolly.scalajs.react.vdom.ReactTagOf[TopNode]
+    final type TagMod                    = japgolly.scalajs.react.vdom.TagMod
+
     @inline final def TagMod   = japgolly.scalajs.react.vdom.TagMod
     @inline final def EmptyTag = japgolly.scalajs.react.vdom.EmptyTag
   }

doc/CHANGELOG-0.10.md

@@ -367,6 +367,12 @@ Unlike the `render` methods, this migration can be automated (see below).
 
 * Upgrade scala-js-dom 0.8.{1 ⇒ 2}.
 
+* Added `ReactTagOf` to provide more specific types for scalatags. `ReactTag` is the kept the same as before for compatibility or if you don't need it.  
+```scala
+val specific: ReactTagOf[html.Div] = div()
+val general: ReactTag = specific
+```
+
 ---
 
 ### Migration commands