Docs: updates issue templates. (#5913)

### What problem does this PR solve?


### Type of change

- [x] Other (please describe):

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -3,13 +3,17 @@ description: Create a bug issue for RAGFlow
 title: "[Bug]: "
 labels: [bug]
 body:
-- type: checkboxes
-  attributes:
-    label: Is there an existing issue for the same bug?
-    description: Please check if an issue already exists for the bug you encountered.
-    options:
-    - label: I have checked the existing issues.
-      required: true
+  - type: checkboxes
+    attributes:
+      label: Self Checks
+      description: "To make sure we get to you in time, please check the following :)"
+      options:
+        - label: I have searched for existing issues [search for existing issues](https://github.com/infiniflow/ragflow/issues), including closed ones.
+          required: true
+        - label: I confirm that I am using English to submit this report ([Language Policy](https://github.com/infiniflow/ragflow/issues/5910)).
+          required: true
+        - label: "Please do not modify this template :) and fill in all the required fields."
+          required: true
 - type: markdown
   attributes:
     value: "Please provide the following information to help us understand the issue."