[docs]: Revamp embedchain docs (#799)

docs/data-sources/pdf-file.mdx

@@ -1,14 +1,17 @@
 ---
-title: 'PDF File'
+title: '📰 PDF file'
 ---
 
-
-### PDF File
-
 To add any pdf file, use the data_type as `pdf_file`. Eg:
 
 ```python
-app.add('a_valid_url_where_pdf_file_can_be_accessed', data_type='pdf_file')
+from embedchain import App
+
+app = App()
+
+app.add('https://arxiv.org/pdf/1706.03762.pdf', data_type='pdf_file')
+app.query("What is the paper 'attention is all you need' about?")
+# Answer: The paper "Attention Is All You Need" proposes a new network architecture called the Transformer, which is based solely on attention mechanisms. It suggests moving away from complex recurrent or convolutional neural networks and instead using attention mechanisms to connect the encoder and decoder in sequence transduction models.
 ```
 
 Note that we do not support password protected pdfs.