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:

检查 GitHub Actions 的 workflow 配置，并将其与链接的 .github/workflows/lint-patterns.yml 示例进行比较，然后查看 pull request #261 中显示的重复运行。完成标准是 markdownlint 每个 pull request 运行一次，同时不丢失 pushes 时所需的 workflow 行为。