fix: Rename Generator to CodeGenerator (#6585)

Stops collisions with ES6's Generator.
The old Blockly.Generator still exists as a name, but is now deprecated.

tests/mocha/jso_deserialization_test.js

@@ -728,47 +728,47 @@ suite('JSO Deserialization', function() {
         this.name = name;
         return this;
       }
-    
+
       insertParameter(parameterModel, index) {
         this.parameters.splice(index, 0, parameterModel);
         return this;
       }
-    
+
       deleteParameter(index) {
         this.parameters.splice(index, 1);
         return this;
       }
-    
+
       setReturnTypes(types) {
         this.returnTypes = types;
         return this;
       }
-    
+
       setEnabled(enabled) {
         this.enabled = enabled;
         return this;
       }
-    
+
       getId() {
         return this.id;
       }
-    
+
       getName() {
         return this.name;
       }
-    
+
       getParameter(index) {
         return this.parameters[index];
       }
-    
+
       getParameters() {
         return [...this.parameters];
       }
-    
+
       getReturnTypes() {
         return this.returnTypes;
       }
-    
+
       getEnabled() {
         return this.enabled;
       }