[core] Polish issue templates

.github/ISSUE_TEMPLATE/1.bug.yml

@@ -4,15 +4,13 @@ labels: ['status: waiting for maintainer']
 body:
   - type: markdown
     attributes:
-      value: |
-        Please provide a searchable summary of the issue in the title above ⬆️.
-
-        Thanks for contributing by creating an issue! ❤️
+      value: Thanks for contributing by creating an issue! ❤️ Please provide a searchable summary of the issue in the title above ⬆️.
   - type: input
     attributes:
       label: Search keywords
-      description: Your issue may have already been reported! List the keywords you've used to search the [existing issues](https://github.com/mui/mui-design-kits/issues). This will also make your issue searchable for others.
-      placeholder: e.g. datagrid column
+      description: |
+        Your issue may have already been reported! First search for duplicates among the [existing issues](https://github.com/mui/mui-design-kits/issues).
+        If your issue isn't a duplicate, great! Please list the keywords you used so people in the future can find this one more easily:
     validations:
       required: true
   - type: checkboxes
@@ -45,7 +43,7 @@ body:
   - type: textarea
     attributes:
       label: Context
-      description: What are you trying to accomplish? How has this issue affected you? Providing context helps us come up with a solution that is more useful in the real world.
+      description: What are you trying to accomplish? Providing context helps us come up with a solution that is more useful in the real world.
   - type: textarea
     attributes:
       label: Your environment

.github/ISSUE_TEMPLATE/2.feature.yml

@@ -4,17 +4,15 @@ labels: ['status: waiting for maintainer']
 body:
   - type: markdown
     attributes:
-      value: |
-        Please provide a searchable summary of the issue in the title above ⬆️.
-
-        Thanks for contributing by creating an issue! ❤️
-  - type: checkboxes
+      value: Thanks for contributing by creating an issue! ❤️ Please provide a searchable summary of the issue in the title above ⬆️.
+  - type: input
     attributes:
-      label: Duplicates
-      description: Please [search the history](https://github.com/mui/mui-design-kits/issues) to see if an issue already exists for the same problem.
-      options:
-        - label: I have searched the existing issues
-          required: true
+      label: Search keywords
+      description: |
+        Your issue may have already been reported! First search for duplicates among the [existing issues](https://github.com/mui/mui-design-kits/issues).
+        If your issue isn't a duplicate, great! Please list the keywords you used so people in the future can find this one more easily:
+    validations:
+      required: true
   - type: checkboxes
     attributes:
       label: Latest version
@@ -33,4 +31,4 @@ body:
   - type: textarea
     attributes:
       label: Motivation
-      description: What are you trying to accomplish? How has the lack of this feature affected you? Providing context helps us come up with a solution that is more useful in the real world.
+      description: What are you trying to accomplish? Providing context helps us come up with a solution that is more useful in the real world.

.github/ISSUE_TEMPLATE/3.support.yml

@@ -9,13 +9,14 @@ body:
         Please provide a searchable summary of the issue in the title above ⬆️.
 
         ⚠️ **Don't use this form if the problem is [a bug](https://github.com/mui/mui-design-kits/issues/new?assignees=&labels=status%3A+needs+triage&template=1.bug.yml) or a [feature request](https://github.com/mui/mui-design-kits/issues/new?assignees=&labels=status%3A+needs+triage&template=2.feature.yml), use the dedicated form instead.**
-  - type: checkboxes
+  - type: input
     attributes:
-      label: Duplicates
-      description: Please [search the history](https://github.com/mui/mui-design-kits/issues) to see if an issue already exists for the same problem.
-      options:
-        - label: I have searched the existing issues
-          required: true
+      label: Search keywords
+      description: |
+        Your issue may have already been reported! First search for duplicates among the [existing issues](https://github.com/mui/mui-design-kits/issues).
+        If your issue isn't a duplicate, great! Please list the keywords you used so people in the future can find this one more easily:
+    validations:
+      required: true
   - type: checkboxes
     attributes:
       label: Latest version

.github/ISSUE_TEMPLATE/4.rfc.yml

@@ -40,4 +40,4 @@ body:
   - type: textarea
     attributes:
       label: Relevant resources/benchmarks 🔗
-      description: Attach any issues, PRs, links, documents, etc… that might be relevant to the RFC.
+      description: Attach any issues, PRs, links, documents, etc… that might be relevant to the RFC..