[Feature] Cleaner Navigation Outline for Nested Steps/Tabs

[NolanTrem]

Problem description

When using nested Steps and Tabs components, the current "On this page" outline repeats the step numbers for each tab variation. If the steps are identical across tabs, I'd prefer to show each step number only once in the outline.

Why would it be useful?

When documenting alternative implementations (e.g., Option A vs Option B) that follow the same steps, the current outline becomes unnecessarily verbose. Since users are following the same step numbers regardless of their chosen option, showing the steps once would provide a cleaner and more focused navigation experience.

Additional context

Version 1 (Steps outside):
<Steps>
  ### Step 1
    <Tabs>
      <Tab title="Option A">
        This is content for Option A in Step 1.
      </Tab>
      <Tab title="Option B">
        This is content for Option B in Step 1.
      </Tab>
    </Tabs>

  ### Step 2
    <Tabs>
      <Tab title="Option A">
        This is content for Option A in Step 2.
      </Tab>
      <Tab title="Option B">
        This is content for Option B in Step 2.
      </Tab>
    </Tabs>
  
  ### Step 3
    This is common content for Step 3.
</Steps>

Version 2 (Tabs outside):
<Tabs>
  <Tab title="Option A">
    <Steps>
      ### Step 1
        This is content for Option A in Step 1.

      ### Step 2
        This is content for Option A in Step 2.

      ### Step 3
        This is common content for Step 3.
    </Steps>
  </Tab>

  <Tab title="Option B">
    <Steps>
      ### Step 1
        This is content for Option B in Step 1.

      ### Step 2
        This is content for Option B in Step 2.

      ### Step 3
        This is common content for Step 3.
    </Steps>
  </Tab>
</Tabs>