message: Fix typos on career + self hosted
diff: <header class="tight">
  <h1>Self-hosted plans</h1>
  <p>
  - Install Gitpod Self-Hosted or <strong>Google Cloud Platform</strong> and
  + Install Gitpod Self-Hosted on <strong>Google Cloud Platform</strong> and
  <strong>K3s</strong>.
  </p>
  </header>
  