Fix code review feedback: clarify async save_to and add context note

Co-authored-by: RobertoPrevato <2576032+RobertoPrevato@users.noreply.github.com>

Author: Copilot

blacksheep/docs/openapi.md

@@ -231,7 +231,7 @@ BlackSheep 2.6.0 adds full OpenAPI documentation support for `FromText` and `Fro
 
 ///
 
-BlackSheep automatically generates OpenAPI documentation for various request body binders:
+BlackSheep automatically generates OpenAPI documentation for various request body binders. The following examples assume the `docs` handler has been set up as described in the [Built-in support](#built-in-support-for-openapi-documentation) section.
 
 #### FromJSON
 

blacksheep/docs/requests.md

@@ -415,7 +415,7 @@ The `FileBuffer` class wraps `SpooledTemporaryFile` and provides these methods:
 - `read(size: int = -1) -> bytes`: Read file content
 - `seek(offset: int, whence: int = 0) -> int`: Change file position
 - `close() -> None`: Close the file
-- `save_to(file_path: str) -> None`: Save file to disk (async)
+- `async save_to(file_path: str) -> None`: Asynchronously save file to disk (must be awaited)
 
 ```python
 from blacksheep import FromFiles, post