chore: add feature request template

PiperOrigin-RevId: 590796188

Author: asyncLiz

.github/ISSUE_TEMPLATE/config.yml

@@ -6,4 +6,4 @@ contact_links:
 
   - name: 💬 Chat
     url: https://lit.dev/discord/
-    about: Alternatively, you can join the Lit Discord and join the \#material channel to talk to the material community and team.
+    about: Alternatively, you can join the Lit Discord and join the `#material` channel to talk to the team.

.github/ISSUE_TEMPLATE/feature.yaml

@@ -0,0 +1,16 @@
+name: ✨ Feature Request
+description: Request a feature to be added to Material Web Components.
+
+body:
+  - type: textarea
+    id: description
+    validations:
+      required: true
+    attributes:
+      label: Description
+      description: |
+        Please describe the feature request in as much detail as possible. Include why the feature is needed, and example code or screenshots to help describe it.
+      placeholder: |
+        Add support for '...'.
+        This is needed to '...'.
+        Requirements, code examples, and screenshots that help describe the feature.