subject -> topic: Fix stream/subject in comments.

static/js/compose_actions.js

@@ -225,7 +225,7 @@ exports.start = function (msg_type, opts) {
     compose_state.recipient(opts.private_message_recipient.replace(/,\s*/g, ", "));
 
     // If the user opens the compose box, types some text, and then clicks on a
-    // different stream/subject, we want to keep the text in the compose box
+    // different stream/topic, we want to keep the text in the compose box
     if (opts.content !== undefined) {
         compose_state.message_content(opts.content);
     }

static/js/floating_recipient_bar.js

@@ -85,10 +85,10 @@ exports.update = function () {
     }
     var current_label = candidate;
 
-    // We now know what the floating stream/subject bar should say.
+    // We now know what the floating stream/topic bar should say.
     // Do we show it?
 
-    // Hide if the bottom of our floating stream/subject label is not
+    // Hide if the bottom of our floating stream/topic label is not
     // lower than the bottom of current_label (since that means we're
     // covering up a label that already exists).
     var header_height = $(current_label).find('.message_header').safeOuterHeight();

static/js/narrow_state.js

@@ -314,7 +314,7 @@ exports.narrowed_by_topic_reply = function () {
 };
 
 // We auto-reply under certain conditions, namely when you're narrowed
-// to a PM (or huddle), and when you're narrowed to some stream/subject pair
+// to a PM (or huddle), and when you're narrowed to some stream/topic pair
 exports.narrowed_by_reply = function () {
     return exports.narrowed_by_pm_reply() ||
             exports.narrowed_by_topic_reply();

static/js/tab_bar.js

@@ -99,7 +99,7 @@ function make_tab_data() {
             tabs.push(make_tab("Search results", false));
         }
 
-        // Third breadcrumb item for stream-subject naarrows
+        // Third breadcrumb item for stream-topic naarrows
         if (filter.has_operator("stream") &&
             filter.has_operator("topic")) {
             var subject = filter.operands("topic")[0];