Everything: Rich text redux (#5625)

* lord save me

* UI/ChatBox: Use the new `defStyle` param for `RenderMarkup`

The previous iteration didn't work because `AddMessage` can't inherit
its color from the PushColor (since we're not doing actual tag stacks
anymore).

* rebase touchup

Content.Server/Power/Components/ExaminableBatteryComponent.cs

@@ -3,6 +3,7 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.Localization;
 using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
+using Robust.Shared.Utility.Markup;
 
 namespace Content.Server.Power.Components
 {
@@ -16,7 +17,7 @@ namespace Content.Server.Power.Components
         [ViewVariables]
         [ComponentDependency] private BatteryComponent? _battery = default!;
 
-        void IExamine.Examine(FormattedMessage message, bool inDetailsRange)
+        void IExamine.Examine(FormattedMessage.Builder message, bool inDetailsRange)
         {
             if (_battery == null)
                 return;