Base: Move GML documentation into subsection

That was the whole point of this endeavour :^)

Base/usr/share/man/man5/GML/Widget-RadioButton.md

@@ -0,0 +1,26 @@
+## Name
+
+GML Radio Button Widget
+
+## Description
+
+Defines a GUI radio button widget.
+
+## Synopsis
+
+`@GUI::RadioButton`
+
+## Examples
+
+```gml
+@GUI::RadioButton {
+    name: "top_radiobutton"
+    text: "Radio 1"
+    checked: true
+}
+
+@GUI::RadioButton {
+    name: "bottom_radiobutton"
+    text: "Radio 2"
+}
+```