fix: correct typos in code comments, docstrings and docs (#13931)

## Summary
- Fix `a image` → `an image` in README and log message
- Fix `colomn` → `column` in table structure recognizer comment
- Fix `formated` → `formatted` in confluence connector docstring
- Fix `tabel of content` → `table of contents` in TOC prompt

## Test plan
- [ ] Documentation and comment changes, no functional impact

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: yuj <yuj@ztjzsoft.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Jin Hai <haijin.chn@gmail.com>

common/data_source/confluence_connector.py

@@ -920,7 +920,7 @@ def extract_text_from_confluence_html(
         confluence_client (Confluence): Confluence client
         fetched_titles (set[str]): The titles of the pages that have already been fetched
     Returns:
-        str: loaded and formated Confluence page
+        str: loaded and formatted Confluence page
     """
     body = confluence_object["body"]
     object_html = body.get("storage", body.get("view", {})).get("value")