github: fix some issue template tags/titles

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 name: Bug report
 description: Found something wrong or broken? If it hasn't already been filed/solved, report it!
-title: "[Bug]: "
+title: "[Bug] "
 labels: ["bug"]
 body:
   - type: checkboxes

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,8 +1,8 @@
 ---
 name: Feature request
 about: Got a good idea that hasn't already been suggested?  Mention it here!
-title: ""
-labels: "feature"
+title: "[Feature] "
+labels: ["feature"]
 assignees: ""
 ---
 

.github/ISSUE_TEMPLATE/packaging.yml

@@ -1,6 +1,6 @@
 name: Packaging
 description: For issues, questions, or requests regarding packaging or distribution.
-title: "[Packaging]: "
+title: "[Packaging] "
 labels: ["packaging"]
 body:
   - type: markdown