[Doc] Add issue templates. (#435)

This PR provides issue templates for bug reports and feature requests.
The templates can improve the efficiency to resolve the problem.

---------

Signed-off-by: Yuchuan <[email protected]>

Author: Seven-Streams

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,37 @@
+name: 🐛 Bug Report
+description: Create a report to help us reproduce and fix the bug
+title: "[Bug] "
+labels: ['Bug']
+
+body:
+  - type: checkboxes
+    attributes:
+      label: Checklist
+      options:
+        - label: 1. I have searched related issues but cannot get the expected help.
+        - label: 2. The bug has not been fixed in the latest version.
+        - label: 3. I have filled all the required information below.
+        - label: 4. The bug report is in English.
+  - type: textarea
+    attributes:
+      label: Describe the bug
+      description: A clear and concise description of what the bug is.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Reproduction
+      description: |
+        Please include a minimal code snippet to reproduce the behavior.
+      placeholder: |
+        A placeholder for the command.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Environment
+      description: |
+        Please provide the version of XGrammar, the serving engine for llms, etc.
+      placeholder: Environment here.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,41 @@
+name: 🚀 Feature Request
+description: Suggest an idea for this project
+title: "[Feature] "
+labels: ['Feature']
+
+body:
+  - type: checkboxes
+    attributes:
+      label: Checklist
+      options:
+        - label: 1. I have searched related issues but cannot get the expected help.
+        - label: 2. The latest version does not have this feature.
+        - label: 3. I have filled all the required information below.
+        - label: 4. The feature request is in English.
+  - type: textarea
+    attributes:
+      label: requested feature
+      description: |
+        Please describe what's the requested feature.
+      placeholder: |
+        A clear and concise description of the requested feature.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Motivation
+      description: |
+        Please describe the motivation for the feature.
+      placeholder: |
+        A clear and concise description of the motivation for the feature.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Alternatives
+      description: |
+        Please describe the alternatives you have considered.
+      placeholder: |
+        A clear and concise description of the alternatives you have considered, if any.
+    validations:
+      required: false