chore: improve issue templates (#10708)

.github/ISSUE_TEMPLATE.md

-<!--
-
-Please note this is an issue tracker, not a support forum.
-For general questions, please use StackOverflow or Slack.
-
-For bugs, please fill out the template below.
-
--->
-
-## What are you doing?
-<!-- Post a minimal, self-contained code sample that reproduces the issue, including models and associations -->
-
-```js
-// code here
-```
-
-## What do you expect to happen?
-_I wanted Foo!_
-
-## What is actually happening?
-_But the output was bar!_
-
-_Output, either JSON or SQL_
-
-
-__Dialect:__ mysql / postgres / sqlite / mssql / any
-__Dialect version:__ XXX
-__Database version:__ XXX
-__Sequelize version:__ XXX
-__Tested with latest release:__ No (If yes, specify that version)
-
-
-**Note :** _Your issue may be ignored OR closed by maintainers if it's not tested against latest version OR does not follow issue template._

.github/ISSUE_TEMPLATE/bug_report.md

+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+<!--
+Please note this is an issue tracker, not a support forum.
+For general questions, please use StackOverflow or Slack.
+-->
+
+## What are you doing?
+<!-- Post a minimal, self-contained code sample that reproduces the issue, including models and associations -->
+
+```js
+// code here
+```
+**To Reproduce**
+Steps to reproduce the behavior:
+1. Define models X, Y, ...
+2. Run the following
+3. See error
+
+## What do you expect to happen?
+_I wanted Foo!_
+
+## What is actually happening?
+_But the output was bar!_
+
+_Output, either JSON or SQL_
+
+## Environment
+Dialect:
+- [ ] mysql
+- [ ] postgres
+- [ ] sqlite
+- [ ] mssql
+- [ ] any
+Dialect **library** version: XXX
+Database version: XXX
+Sequelize version: XXX
+Node Version: XXX
+OS: XXX
+If TypeScript related: TypeScript version: XXX
+Tested with latest release:
+- [ ] No
+- [ ] Yes, specify that version: 

.github/ISSUE_TEMPLATE/documentational-issue.md

+---
+name: Documentational issue
+about: Documentation is unclear, or otherwise insufficient/misleading
+title: ''
+labels: documentation
+assignees: ''
+
+---
+
+## What was unclear/insufficient/not covered in the documentation
+
+### If possible: Provide some suggestion how we can enhance the docs
+
+> Text goes here

.github/ISSUE_TEMPLATE/feature_request.md

+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: feature
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Why should this be in Sequelize**
+Short explanation why this should be part of Sequelize rather than a separate package.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Usage example**
+How can the requested feature be used to approach the problem it's supposed to solve.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.