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>

deepdoc/README.md

@@ -98,7 +98,7 @@ We use vision information to resolve problems as human being.
      ```bash
         python deepdoc/vision/t_recognizer.py --inputs=path_to_images_or_pdfs --threshold=0.2 --mode=tsr --output_dir=path_to_store_result
      ```
-    The inputs could be directory to images or PDF, or a image or PDF. 
+    The inputs could be directory to images or PDF, or an image or PDF. 
     You can look into the folder 'path_to_store_result' where has both images and html pages which demonstrate the detection results as following:
     <div align="center" style="margin-top:20px;margin-bottom:20px;">
     <img src="https://github.com/infiniflow/ragflow/assets/12318111/cb24e81b-f2ba-49f3-ac09-883d75606f4c" width="1000"/>

deepdoc/parser/pdf_parser.py

@@ -708,7 +708,7 @@ class RAGFlowPdfParser:
     def __ocr(self, pagenum, img, chars, ZM=3, device_id: int | None = None):
         start = timer()
         bxs = self.ocr.detect(np.array(img), device_id)
-        logging.info(f"__ocr detecting boxes of a image cost ({timer() - start}s)")
+        logging.info(f"__ocr detecting boxes of an image cost ({timer() - start}s)")
 
         start = timer()
         if not bxs:

deepdoc/vision/table_structure_recognizer.py

@@ -394,7 +394,7 @@ class TableStructureRecognizer(Recognizer):
 
     @staticmethod
     def __desc_table(cap, hdr_rowno, tbl, is_english):
-        # get text of every colomn in header row to become header text
+        # get text of every column in header row to become header text
         clmno = len(tbl[0])
         rowno = len(tbl)
         headers = {}