Add an installation method field to the bug report template (#8711)

We can guess the installation method from the version tag and platform
in some cases but it would be useful to have this be explicit for the
sake of debugging packager-specific problems.

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -55,6 +55,16 @@ body:
       placeholder: wezterm 20220101-133340-7edc5b5a
     validations:
       required: true
+  - type: input
+    id: installation-method
+    attributes:
+      label: Installation Method
+      description: >
+        How you installed Helix - from a package manager like Homebrew or the
+        AUR, built from source, downloaded a binary from the releases page, etc.
+      placeholder: "source / brew / nixpkgs / flake / releases page"
+    validations:
+      required: true
   - type: input
     id: helix-version
     attributes: