handle exceptions during jsonrpc init

There are too many exceptions to catch individually, including chronos raising CatchableError exceptions in await expansion. There are also many other errors captured inside of the new proc with CatchableError. Instead of making it more complicated and harder to read, I think sticking with excepting CatchableError inside of convertError is a sensible solution

ethers/providers/jsonrpc.nim

@@ -53,7 +53,7 @@ template convertError(body) =
   except JsonRpcError as error:
     raiseJsonRpcProviderError(error.msg)
   except CatchableError as error:
-    raise newException(JsonRpcProviderError, error.msg)
+    raiseJsonRpcProviderError(error.msg)
 
 # Provider
 
@@ -72,20 +72,21 @@ proc new*(
   var client: RpcClient
   var subscriptions: JsonRpcSubscriptions
 
-  proc initialize {.async.} =
-    case parseUri(url).scheme
-    of "ws", "wss":
-      let websocket = newRpcWebSocketClient(getHeaders = jsonHeaders)
-      await websocket.connect(url)
-      client = websocket
-      subscriptions = JsonRpcSubscriptions.new(websocket)
-    else:
-      let http = newRpcHttpClient(getHeaders = jsonHeaders)
-      await http.connect(url)
-      client = http
-      subscriptions = JsonRpcSubscriptions.new(http,
-                                               pollingInterval = pollingInterval)
-    subscriptions.init()
+  proc initialize {.async: (raises:[JsonRpcProviderError]).} =
+    convertError:
+      case parseUri(url).scheme
+      of "ws", "wss":
+        let websocket = newRpcWebSocketClient(getHeaders = jsonHeaders)
+        await websocket.connect(url)
+        client = websocket
+        subscriptions = JsonRpcSubscriptions.new(websocket)
+      else:
+        let http = newRpcHttpClient(getHeaders = jsonHeaders)
+        await http.connect(url)
+        client = http
+        subscriptions = JsonRpcSubscriptions.new(http,
+                                                pollingInterval = pollingInterval)
+      subscriptions.init()
 
   proc awaitClient: Future[RpcClient] {.async:(raises:[JsonRpcProviderError]).} =
     convertError:
@@ -97,9 +98,8 @@ proc new*(
       await initialized
       return subscriptions
 
-  convertError:
-    initialized = initialize()
-    return JsonRpcProvider(client: awaitClient(), subscriptions: awaitSubscriptions())
+  initialized = initialize()
+  return JsonRpcProvider(client: awaitClient(), subscriptions: awaitSubscriptions())
 
 proc callImpl(
   client: RpcClient,