slate-react placeholder unable to change the style

[meowWhat]

Problem

the leaf with placeholder use the inline-styles，user cannot change the placeholder style ，Can I make the placeholder render configurable .

Even if I rewrite RenderLeaf, I can't find the placeholder node by symbol tag .

[ianstormtaylor]

I think if people want to do this it should like be as a renderPlaceholder= overrideable prop, which defaults to the current built-in behavior.

[juliankrispel]

I think if people want to do this it should like be as a renderPlaceholder= overrideable prop, which defaults to the current built-in behavior.

#4190