docs: Remove old Markdown issue template (#15556)

* chore: Remove old Markdown issue template

This template in Markdown format has been superseded by the forms in the
`.github./ISSUE_TEMPLATE` directory. When viewing this file in the
GitHub UI, it shows a warning:

> You are using an old version of issue templates. Please update to the
> new issue template workflow. [Learn more][1]

[1]: https://docs.github.com/articles/about-issue-and-pull-request-templates

* docs: Link to new issue template chooser

All of these direct links to our old Markdown-based issue templates are
broken and just lead to an empty form. I could link directly to the
relevant new yml template, but standardizing on `/issues/new/choose`
seems safer as it'll continue working even if we change the available
templates.

docs/developer-guide/contributing/changes.md

@@ -1,6 +1,6 @@
 # Change Requests
 
-If you'd like to request a change to ESLint, please [create a new issue](https://github.com/eslint/eslint/issues/new?template=CHANGE.md) on GitHub. Be sure to include the following information:
+If you'd like to request a change to ESLint, please [create a new issue](https://github.com/eslint/eslint/issues/new/choose) on GitHub. Be sure to include the following information:
 
 1. The version of ESLint you are using.
 1. The problem you want to solve.

docs/developer-guide/contributing/new-rules.md

@@ -19,7 +19,7 @@ Even though these are the formal criteria for inclusion, each rule is evaluated
 
 ## Proposing a Rule
 
-If you want to propose a new rule, please see how to [create a pull request](/docs/developer-guide/contributing/pull-requests) or submit an issue by filling out a [new rule template](https://github.com/eslint/eslint/issues/new?template=NEW_RULE.md).
+If you want to propose a new rule, please see how to [create a pull request](/docs/developer-guide/contributing/pull-requests) or submit an issue by filling out a [new rule template](https://github.com/eslint/eslint/issues/new/choose).
 
 We need all of this information in order to determine whether or not the rule is a good core rule candidate.
 

docs/developer-guide/contributing/reporting-bugs.md

@@ -1,6 +1,6 @@
 # Reporting Bugs
 
-If you think you've found a bug in ESLint, please [create a new issue](https://github.com/eslint/eslint/issues/new) or a [pull request](/docs/developer-guide/contributing/pull-requests.md) on GitHub.
+If you think you've found a bug in ESLint, please [create a new issue](https://github.com/eslint/eslint/issues/new/choose) or a [pull request](/docs/developer-guide/contributing/pull-requests.md) on GitHub.
 
 Please include as much detail as possible to help us properly address your issue. If we need to triage issues and constantly ask people for more detail, that's time taken away from actually fixing issues. Help us be as efficient as possible by including a lot of detail in your issues.
 

docs/developer-guide/contributing/rule-changes.md

@@ -4,7 +4,7 @@ Occasionally, a core ESLint rule needs to be changed. This is not necessarily a
 
 ## Proposing a Rule Change
 
-To propose a change to an existing rule, [create a pull request](/docs/developer-guide/contributing/pull-requests.md) or [new issue](https://github.com/eslint/eslint/issues/new?template=RULE_CHANGE.md) and fill out the template.
+To propose a change to an existing rule, [create a pull request](/docs/developer-guide/contributing/pull-requests.md) or [new issue](https://github.com/eslint/eslint/issues/new/choose) and fill out the template.
 
 We need all of this information in order to determine whether or not the change is a good candidate for inclusion.