api!: consistent spelling of "canceled" with a single "l"

This is how it is spelled in iOS UI and Android APIs.

deltachat-jsonrpc/src/api.rs

@@ -1809,13 +1809,13 @@ impl CommandApi {
 
     /// Offers a backup for remote devices to retrieve.
     ///
-    /// Can be cancelled by stopping the ongoing process.  Success or failure can be tracked
+    /// Can be canceled by stopping the ongoing process.  Success or failure can be tracked
     /// via the `ImexProgress` event which should either reach `1000` for success or `0` for
     /// failure.
     ///
     /// This **stops IO** while it is running.
     ///
-    /// Returns once a remote device has retrieved the backup, or is cancelled.
+    /// Returns once a remote device has retrieved the backup, or is canceled.
     async fn provide_backup(&self, account_id: u32) -> Result<()> {
         let ctx = self.get_context(account_id).await?;
 
@@ -1881,7 +1881,7 @@ impl CommandApi {
     /// This retrieves the backup from a remote device over the network and imports it into
     /// the current device.
     ///
-    /// Can be cancelled by stopping the ongoing process.
+    /// Can be canceled by stopping the ongoing process.
     ///
     /// Do not forget to call start_io on the account after a successful import,
     /// otherwise it will not connect to the email server.

deltachat-jsonrpc/src/api/types/calls.rs

@@ -20,7 +20,7 @@ pub struct JsonrpcCallInfo {
 
     /// Call state.
     ///
-    /// For example, if the call is accepted, active, cancelled, declined etc.
+    /// For example, if the call is accepted, active, canceled, declined etc.
     pub state: JsonrpcCallState,
 }
 
@@ -68,13 +68,13 @@ pub enum JsonrpcCallState {
     /// that was declined before the timeout.
     Declined,
 
-    /// Outgoing call that has been cancelled on our side
+    /// Outgoing call that has been canceled on our side
     /// before receiving a response.
     ///
-    /// Incoming calls cannot be cancelled,
-    /// on the receiver side cancelled calls
+    /// Incoming calls cannot be canceled,
+    /// on the receiver side canceled calls
     /// usually result in missed calls.
-    Cancelled,
+    Canceled,
 }
 
 impl JsonrpcCallState {
@@ -87,7 +87,7 @@ impl JsonrpcCallState {
             CallState::Completed { duration } => JsonrpcCallState::Completed { duration },
             CallState::Missed => JsonrpcCallState::Missed,
             CallState::Declined => JsonrpcCallState::Declined,
-            CallState::Cancelled => JsonrpcCallState::Cancelled,
+            CallState::Canceled => JsonrpcCallState::Canceled,
         };
 
         Ok(jsonrpc_call_state)