Markdownlint Action is running twice

I noticed that the markdownlint GitHub Action that we have is running twice on the same PR.
It is mostly a cosmetic problem and it also might be a bit confusing for people.

I know that we could prevent it by limiting the action workflow execution to pushes to master like in this GHA configuration. However that seems to have other undesirable consequences.

I wonder if there is some way to do this?

Example:

See the bottom of https://github.com/InnerSourceCommons/InnerSourcePatterns/pull/261/

Screenshot:

檢查 GitHub Actions 的 workflow 設定，並與連結的 .github/workflows/lint-patterns.yml 範例進行比較，然後檢視 pull request #261 中顯示的重複執行。完成標準是 markdownlint 每個 pull request 執行一次，同時不遺失 pushes 時所需的 workflow 行為。