Avoid using gRPC when generic RPC systems have same properties

The concept of "streaming" is supported by multiple protocols including gRPC, but also others.

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

semantic_conventions/trace/rpc.yaml

@@ -2,7 +2,7 @@ groups:
   - id: rpc
     prefix: rpc
     brief: 'This document defines semantic conventions for remote procedure calls.'
-    events: [rpc.grpc.message]
+    events: [rpc.message]
     attributes:
       - id: system
         type: string
@@ -142,10 +142,10 @@ groups:
         note: >
           This is always required for jsonrpc. See the note in the general
           RPC conventions for more information.
-  - id: rpc.grpc.message
-    prefix: "message"  # TODO: Change the prefix to rpc.grpc.message?
+  - id: rpc.message
+    prefix: "message"  # TODO: Change the prefix to rpc.message?
     type: event
-    brief: "gRPC received/sent message."
+    brief: "RPC received/sent message."
     attributes:
       - id: type
         type:

specification/trace/semantic_conventions/rpc.md

@@ -152,7 +152,7 @@ client and server spans.
 
 The event name MUST be `"message"`.
 
-<!-- semconv rpc.grpc.message -->
+<!-- semconv rpc.message -->
 | Attribute  | Type | Description  | Examples  | Required |
 |---|---|---|---|---|
 | `message.type` | string | Whether this is a received or sent message. | `SENT` | No |