Enhance XCUI demo text editing and host bridge

Assets/XCUI/NewEditor/Demo/View.xcui

@@ -50,6 +50,10 @@
           min-width="240"
           placeholder="Type a command or note for XCUI..."
           value="" />
+        <Text
+          id="promptMeta"
+          text="Single-line input, Enter submits"
+          style="Meta" />
       </Column>
     </Card>
     <Card id="notesCard" style="MetricCard">
@@ -61,8 +65,13 @@
           width="stretch"
           min-width="240"
           rows="4"
+          show-line-numbers="true"
           placeholder="Write multiline notes, prompts, or todos for the current screen..."
           value="" />
+        <Text
+          id="notesMeta"
+          text="Multiline input, click caret, Tab indent"
+          style="Meta" />
       </Column>
     </Card>
     <Button id="toggleAccent" action="demo.toggleAccent" style="AccentButton">