docs: add comments (#10)

Signed-off-by: Rishav Dhar <19497993+rdhar@users.noreply.github.com>

Author: rdhar

README.md

@@ -22,8 +22,9 @@ Supported event triggers:
 
 ```yaml
 on:
+  issue_comment:
+  merge_group:
   push:
-    branches: [main]
 
 jobs:
   test:

action.yml

@@ -28,6 +28,7 @@ runs:
           # Fallback on 0 if the PR number is not found.
           number=${{ github.event.number || github.event.issue.number || 0 }}
         fi
+        # Fallback on empty string if the branch is not found.
         branch=${{ github.ref_name || github.head_ref || github.ref || '' }}
         echo "branch=$branch" >> "$GITHUB_OUTPUT"
         echo "number=$number" >> "$GITHUB_OUTPUT"