add clarifying comment for default strat, add examples

Author: satvu

src/proto/FunctionRpc.proto

@@ -247,8 +247,10 @@ message FunctionEnvironmentReloadRequest {
 message FunctionEnvironmentReloadResponse {
   enum CapabilitiesUpdateStrategy {
     // overwrites existing values and appends new ones
+    // ex. worker init: {A: foo, B: bar} + env reload: {A:foo, B: foo, C: foo} -> {A: foo, B: foo, C: foo}
     merge = 0;
     // existing capabilities are cleared and new capabilities are applied
+    // ex. worker init: {A: foo, B: bar} + env reload: {A:foo, C: foo} -> {A: foo, C: foo}
     replace = 1;
   }
   // After specialization, worker sends capabilities & metadata.
@@ -260,7 +262,8 @@ message FunctionEnvironmentReloadResponse {
 
   // Status of the response
   StatusResult result = 3;
-
+  
+  // If no strategy is defined, the host will default to merge
   CapabilitiesUpdateStrategy capabilities_update_strategy = 4;
 }