✨ Add support for declaring UploadFile parameters without explicit File() (#4469)

docs/en/docs/tutorial/request-files.md

@@ -17,7 +17,7 @@ Import `File` and `UploadFile` from `fastapi`:
 {!../../../docs_src/request_files/tutorial001.py!}
 ```
 
-## Define `File` parameters
+## Define `File` Parameters
 
 Create file parameters the same way you would for `Body` or `Form`:
 
@@ -41,7 +41,7 @@ Have in mind that this means that the whole contents will be stored in memory. T
 
 But there are several cases in which you might benefit from using `UploadFile`.
 
-## `File` parameters with `UploadFile`
+## `File` Parameters with `UploadFile`
 
 Define a `File` parameter with a type of `UploadFile`:
 
@@ -51,6 +51,7 @@ Define a `File` parameter with a type of `UploadFile`:
 
 Using `UploadFile` has several advantages over `bytes`:
 
+* You don't have to use `File()` in the default value.
 * It uses a "spooled" file:
     * A file stored in memory up to a maximum size limit, and after passing this limit it will be stored in disk.
 * This means that it will work well for large files like images, videos, large binaries, etc. without consuming all the memory.
@@ -113,7 +114,31 @@ The way HTML forms (`<form></form>`) sends the data to the server normally uses
 
     This is not a limitation of **FastAPI**, it's part of the HTTP protocol.
 
-## Multiple file uploads
+## Optional File Upload
+
+You can make a file optional by using standard type annotations:
+
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="9  17"
+    {!> ../../../docs_src/request_files/tutorial001_02.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    ```Python hl_lines="7  14"
+    {!> ../../../docs_src/request_files/tutorial001_02_py310.py!}
+    ```
+
+## `UploadFile` with Additional Metadata
+
+You can also use `File()` with `UploadFile` to set additional parameters in `File()`, for example additional metadata:
+
+```Python hl_lines="13"
+{!../../../docs_src/request_files/tutorial001_03.py!}
+```
+
+## Multiple File Uploads
 
 It's possible to upload several files at the same time.
 
@@ -140,6 +165,22 @@ You will receive, as declared, a `list` of `bytes` or `UploadFile`s.
 
     **FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette.
 
+### Multiple File Uploads with Additional Metadata
+
+And the same way as before, you can use `File()` to set additional parameters, even for `UploadFile`:
+
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="18"
+    {!> ../../../docs_src/request_files/tutorial003.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    ```Python hl_lines="16"
+    {!> ../../../docs_src/request_files/tutorial003_py39.py!}
+    ```
+
 ## Recap
 
 Use `File` to declare files to be uploaded as input parameters (as form data).