doc: direct users to ask questions instead of raising issues

Author: alex-courtis

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,5 +1,5 @@
 name: Bug report
-description: Report a problem with nvim-tree
+description: Report a problem with nvim-tree. Questions should be asked by starting a [Q&A discussion](https://github.com/kyazdani42/nvim-tree.lua/discussions/new).
 labels: [bug]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,6 +1,6 @@
 ---
 name: Feature request
-about: Suggest an idea for this project
+about: Suggest an idea for this project. Questions should be asked by starting a [Q&A discussion](https://github.com/kyazdani42/nvim-tree.lua/discussions/new).
 title: ''
 labels: feature request
 assignees: ''