Update protobuf documentation

Author: g3force

proto/ssl_gc_api.proto

@@ -8,25 +8,42 @@ import "ssl_gc_engine.proto";
 
 import "google/protobuf/duration.proto";
 
+// Message format that is pushed from the GC to the client
 message Output {
+    // The current match state
     optional State match_state = 1;
+    // The current GC state
     optional GcState gc_state = 2;
+    // The protocol
     optional Protocol protocol = 3;
 }
 
+// The game protocol
 message Protocol {
+    // Is this a delta only?
+    // Entries that were already sent are not sent again, because the protocol is immutable anyway.
+    // But if the game is reset, the whole protocol must be replaced. That's what this flag is for.
     optional bool delta = 1;
+    // The (delta) list of entries
     repeated ProtocolEntry entry = 2;
 }
 
+// A protocol entry of a change
 message ProtocolEntry {
+    // Id of the entry
     optional int32 id = 1;
+    // The change that was made
     optional Change change = 2;
+    // The match time elapsed when this change was made
     optional google.protobuf.Duration match_time_elapsed = 3;
+    // The stage time elapsed when this change was made
     optional google.protobuf.Duration stage_time_elapsed = 4;
 }
 
+// Message format that can be send from the client to the GC
 message Input {
+    // A change to be enqueued into the GC engine
     optional Change change = 1;
+    // Reset the match
     optional bool reset_match = 2;
 }

proto/ssl_gc_ci.proto

@@ -7,11 +7,14 @@ import "ssl_gc_referee_message.proto";
 
 // The input format to the GC
 message CiInput {
+    // New unix timestamp in [ns] for the GC
     optional int64 timestamp = 1;
+    // New tracker packet with ball and robot data
     optional TrackerWrapperPacket tracker_packet = 2;
 }
 
 // The output format of the GC response
 message CiOutput {
+    // Latest referee message
     optional Referee referee_msg = 1;
 }