Fix issue templates + add docs template (#2399)

The template weren't applying the default labels ever since I renamed
the labels.

There has been enough issues about documentation opened recently so it's
probably worth a template for it.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,8 +1,8 @@
 ---
 name: Bug report
-about: Create a report to help us improve
+about: Create a report to help us improve Black's quality
 title: ""
-labels: bug
+labels: "T: bug"
 assignees: ""
 ---
 

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,12 @@
+# See also: https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository#configuring-the-template-chooser
+
+# This is the default and blank issues are useful so let's keep 'em.
+blank_issues_enabled: true
+
+contact_links:
+  - name: Chat on Python Discord
+    url: https://discord.gg/RtVdv86PrH
+    about: |
+      User support, questions, and other lightweight requests can be
+      handled via the \#black-formatter text channel we have on Python
+      Discord.

.github/ISSUE_TEMPLATE/docs-issue.md

@@ -0,0 +1,27 @@
+---
+name: Documentation
+about: Report a problem with or suggest something for the documentation
+title: ""
+labels: "T: documentation"
+assignees: ""
+---
+
+**Is this related to a problem? Please describe.**
+
+<!-- A clear and concise description of what the problem is.
+e.g. I'm always frustrated when [...] / I wished that [...] -->
+
+**Describe the solution you'd like**
+
+<!-- A clear and concise description of what you want to
+happen or see changed. -->
+
+**Describe alternatives you've considered**
+
+<!-- A clear and concise description of any
+alternative solutions or features you've considered. -->
+
+**Additional context**
+
+<!-- Add any other context or screenshots about the issue
+here. -->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an idea for this project
 title: ""
-labels: enhancement
+labels: "T: enhancement"
 assignees: ""
 ---
 

.github/ISSUE_TEMPLATE/style_issue.md

@@ -2,7 +2,7 @@
 name: Style issue
 about: Help us improve the Black style
 title: ""
-labels: design
+labels: "T: design"
 assignees: ""
 ---