chore: update comment message

src/compiler.js

@@ -312,10 +312,10 @@ var Compiler = Object.extend({
         var name = node.value;
         var v;
 
-        // if current scope has name in frame.store, than mean there is
-        // an formal parameter variable name as `node.value`, so if this
-        // parameter name can lookup from scope context, than parameter will
-        // replace by scope value.
+        // if current scope has `node.value` in frame.store, that mean there is
+        // an formal parameter variable name as `node.value`. if just lookup
+        // variable, when parameter name can lookup from scope context, the
+        // parameter may replace by scope value.
         // see https://github.com/mozilla/nunjucks/issues/774
         if(!frame.has(name) && (v = frame.lookup(name))) {
             this.emit(v);