docs: Update return types for arun() and arun_many() to RunManyReturn (#1543)

[YuriNachos]

🎯 Summary

Fixes #1543

📝 Description

The documentation was incorrectly stating that arun() returns CrawlResult and arun_many() returns Union[List[CrawlResult], AsyncGenerator[CrawlResult, None]]. However, both methods actually return RunManyReturn, causing issues with IDE auto-completion and type hints.

🔧 Changes

• docs/md_v2/api/async-webcrawler.md:

  • Changed arun() return type from CrawlResult to RunManyReturn
  • Changed arun_many() return type from List[CrawlResult] to RunManyReturn

• docs/md_v2/api/arun_many.md:

  • Changed function signature return type from Union[List[CrawlResult], AsyncGenerator[CrawlResult, None]] to RunManyReturn
  • Updated docstring and descriptions to reflect that RunManyReturn contains either a list of results or an async generator

✅ Actual Return Types (from source code)

# crawl4ai/async_webcrawler.py:204
async def arun(...) -> RunManyReturn:

# crawl4ai/async_webcrawler.py:665
async def arun_many(...) -> RunManyReturn:

Co-Authored-By: Claude [email protected]