Simplify some Option / Result / ? operator patterns (#8653)

* Simplify some Option / Result / ? operator patterns

When those match a combinator exactly.

Tool-aided by [comby-rust](https://github.com/huitseeker/comby-rust).

* adjust after review

* adjust post-review

substrate/client/offchain/src/api/http.rs

@@ -183,10 +183,7 @@ impl HttpApi {
 	) -> Result<(), HttpError> {
 		// Extract the request from the list.
 		// Don't forget to add it back if necessary when returning.
-		let mut request = match self.requests.remove(&request_id) {
-			None => return Err(HttpError::Invalid),
-			Some(r) => r,
-		};
+		let mut request = self.requests.remove(&request_id).ok_or_else(|| HttpError::Invalid)?;
 
 		let mut deadline = timestamp::deadline_to_future(deadline);
 		// Closure that writes data to a sender, taking the deadline into account. Can return `Ok`