issue_template: update feature request

Make a more detailed form for filing a feature request. This will help
steer users towards more helpful feature requests, similar to our bug
reporting.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

.github/ISSUE_TEMPLATE/feature-request.md

@@ -1,15 +0,0 @@
----
-name: Feature request
-about: Ask for a new feature to be added (module, program, etc.)
-title: ''
-labels: feature request
-assignees: rycee, berbiche
-
----
-
-<!--
-Note: Please search to see if the feature has already been requested
--->
-
-### Description
-

.github/ISSUE_TEMPLATE/feature-request.yaml

@@ -0,0 +1,38 @@
+name: "✨ Feature Request"
+description: "Suggest an improvement to Home Manager"
+title: "[Feature Request] "
+labels: ["feature request"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thank you for contributing to Home Manager!
+
+        Before you open a new issue, please search the existing issues to see if your feature has already been requested or discussed.
+  - type: markdown
+    attributes:
+      value: "## 🔧 Existing Module Improvement"
+  - type: input
+    id: existing-module-name
+    attributes:
+      label: Module Name
+      description: "What is the name of the module?"
+      placeholder: "e.g., programs.git"
+  - type: textarea
+    id: existing-module-feature
+    attributes:
+      label: Requested Feature
+      description: "Please describe the new feature or improvement in detail."
+  - type: textarea
+    id: existing-module-limitation
+    attributes:
+      label: Current Limitations
+      description: "Why can't your goal be achieved with the current implementation? Please be specific."
+  - type: markdown
+    attributes:
+      value: "---"
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional Context
+      description: Add any other context, screenshots, or configuration examples about the feature request here.