docs: update discuss.frappe.io link in template (#9358)

* chore(docs): updated templates

* docs: update link for markdown compatibility

.github/CONTRIBUTING.md

@@ -6,7 +6,7 @@ Feature requests are also a great way to take the product forward. New ideas can
 
 When you are raising an Issue, you should keep a few things in mind. Remember that the developer does not have access to your machine so you must give all the information you can while raising an Issue. If you are suggesting a feature, you should be very clear about what you want.
 
-The Issue list is not the right place to ask a question or start a general discussion. If you want to do that , then the right place is the forum [https://discuss.frappe.io](https://discuss.frappe.io).
+The Issue list is not the right place to ask a question or start a general discussion. If you want to do that , then the right place is the forum ~~<https://discuss.frappe.io>~~ => [stackoverflow](https://stackoverflow.com/questions/tagged/frappe) tagged under `frappe`.
 
 ### Reply and Closing Policy
 

.github/ISSUE_TEMPLATE/bug_report.md

@@ -8,7 +8,7 @@ labels: bug
 Welcome to the Frappe Framework issue tracker! Before creating an issue, please heed the following:
 
 1. This tracker should only be used to report bugs and request features / enhancements to Frappe
-    - For questions and general support, use https://discuss.frappe.io
+    - For questions and general support, use https://stackoverflow.com/questions/tagged/frappe
     - For documentation issues, refer to https://frappe.io/docs/user/en or the developer cheetsheet https://github.com/frappe/frappe/wiki/Developer-Cheatsheet
 2. Use the search function before creating a new issue. Duplicates will be closed and directed to
    the original discussion.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -8,7 +8,7 @@ labels: feature-request
 Welcome to the Frappe Framework issue tracker! Before creating an issue, please heed the following:
 
 1. This tracker should only be used to report bugs and request features / enhancements to Frappe
-    - For questions and general support, refer to https://discuss.frappe.io
+    - For questions and general support, refer to https://stackoverflow.com/questions/tagged/frappe
     - For documentation issues, use https://frappe.io/docs/user/en or the developer cheetsheet https://github.com/frappe/frappe/wiki/Developer-Cheatsheet
 2. Use the search function before creating a new issue. Duplicates will be closed and directed to
    the original discussion.

.github/ISSUE_TEMPLATE/question-about-using-frappe.md

@@ -6,7 +6,7 @@ labels: invalid
 
 Please post on our forums:
 
-for questions about using the `Frappe Framework`: https://discuss.frappe.io
+for questions about using the `Frappe Framework`: ~~https://discuss.frappe.io~~ => [stackoverflow](https://stackoverflow.com/questions/tagged/frappe) tagged under `frappe`
 
 for questions about using `ERPNext`: https://discuss.erpnext.com