Rename 'target usernames' with 'target recipients' in Composer (#8606)

* Reapply "Rename 'target usernames' with 'target recipients' in Composer"

This reverts commit 9fe11d0fc3 which
reverted ebb288dc2c.

* DEV: Add test for replying to PM

test/javascripts/acceptance/composer-test.js.es6

@@ -831,3 +831,20 @@ QUnit.test("Image resizing buttons", async assert => {
     "it does not unescapes script tags in code blocks"
   );
 });
+
+QUnit.test("can reply to a private message", async assert => {
+  let submitted;
+
+  /* global server */
+  server.post("/posts", () => {
+    submitted = true;
+    return [200, { "Content-Type": "application/json" }, {}];
+  });
+
+  await visit("/t/34");
+  await click(".topic-post:eq(0) button.reply");
+  await fillIn(".d-editor-input", "this is the *content* of the reply");
+  await click("#reply-control button.create");
+
+  assert.ok(submitted);
+});

test/javascripts/models/composer-test.js.es6

@@ -396,3 +396,15 @@ QUnit.test("allows featured link before choosing a category", assert => {
   );
   assert.ok(composer.get("canEditTopicFeaturedLink"), "can paste link");
 });
+
+QUnit.test("targetRecipientsArray contains types", assert => {
+  let composer = createComposer({
+    targetRecipients: "test,codinghorror,staff,foo@bar.com"
+  });
+  assert.ok(composer.targetRecipientsArray, [
+    { type: "group", name: "test" },
+    { type: "user", name: "codinghorror" },
+    { type: "group", name: "staff" },
+    { type: "email", name: "foo@bar.com" }
+  ]);
+});