ui: Rename stream to channel in user-facing strings

Fixes: zulip#630

Author: Khader-1

assets/l10n/app_en.arb

@@ -192,7 +192,7 @@
   "@composeBoxDmContentHint": {
     "description": "Hint text for content input when sending a message to one other person.",
     "placeholders": {
-      "user": {"type": "String", "example": "stream name"}
+      "user": {"type": "String", "example": "channel name"}
     }
   },
   "composeBoxGroupDmContentHint": "Message group",
@@ -205,19 +205,19 @@
   },
   "composeBoxStreamContentHint": "Message #{stream} > {topic}",
   "@composeBoxStreamContentHint": {
-    "description": "Hint text for content input when sending a message to a stream",
+    "description": "Hint text for content input when sending a message to a channel",
     "placeholders": {
-      "stream": {"type": "String", "example": "stream name"},
+      "stream": {"type": "String", "example": "channel name"},
       "topic": {"type": "String", "example": "topic name"}
     }
   },
   "composeBoxSendTooltip": "Send",
   "@composeBoxSendTooltip":  {
     "description": "Tooltip for send button in compose box."
   },
-  "composeBoxUnknownStreamName": "(unknown stream)",
+  "composeBoxUnknownStreamName": "(unknown channel)",
   "@composeBoxUnknownStreamName": {
-    "description": "Replacement name for stream when it cannot be found in the store."
+    "description": "Replacement name for channel when it cannot be found in the store."
   },
   "composeBoxTopicHintText": "Topic",
   "@composeBoxTopicHintText":  {
@@ -344,9 +344,9 @@
   "@topicValidationErrorMandatoryButEmpty": {
     "description": "Topic validation error when topic is required but was empty."
   },
-  "subscribedToNStreams": "Subscribed to {num, plural, =0{no streams} =1{1 stream} other{{num} streams}}",
+  "subscribedToNStreams": "Subscribed to {num, plural, =0{no channels} =1{1 channel} other{{num} channels}}",
   "@subscribedToNStreams": {
-    "description": "Test page label showing number of streams user is subscribed to.",
+    "description": "Test page label showing number of channels user is subscribed to.",
     "placeholders": {
       "num": {"type": "int", "example": "4"}
     }

lib/notifications/display.dart

@@ -96,7 +96,7 @@ class NotificationDisplayManager {
       FcmMessageStreamRecipient(:var streamName?, :var topic) =>
         '$streamName > $topic',
       FcmMessageStreamRecipient(:var topic) =>
-        '(unknown stream) > $topic', // TODO get stream name from data
+        '(unknown channel) > $topic', // TODO get stream name from data
       FcmMessageDmRecipient(:var allRecipientIds) when allRecipientIds.length > 2 =>
         zulipLocalizations.notifGroupDmConversationLabel(
           data.senderFullName, allRecipientIds.length - 2), // TODO use others' names, from data

lib/widgets/app.dart

@@ -282,7 +282,7 @@ class HomePage extends StatelessWidget {
           ElevatedButton(
             onPressed: () => Navigator.push(context,
               SubscriptionListPage.buildRoute(context: context)),
-            child: const Text("Subscribed streams")),
+            child: const Text("Subscribed channels")),
           const SizedBox(height: 16),
           ElevatedButton(
             onPressed: () => Navigator.push(context,

lib/widgets/message_list.dart

@@ -148,13 +148,13 @@ class MessageListAppBarTitle extends StatelessWidget {
       case StreamNarrow(:var streamId):
         final store = PerAccountStoreWidget.of(context);
         final stream = store.streams[streamId];
-        final streamName = stream?.name ?? '(unknown stream)';
+        final streamName = stream?.name ?? '(unknown channel)';
         return _buildStreamRow(stream, streamName);
 
       case TopicNarrow(:var streamId, :var topic):
         final store = PerAccountStoreWidget.of(context);
         final stream = store.streams[streamId];
-        final streamName = stream?.name ?? '(unknown stream)';
+        final streamName = stream?.name ?? '(unknown channel)';
         return _buildStreamRow(stream, "$streamName > $topic");
 
       case DmNarrow(:var otherRecipientIds):

lib/widgets/subscription_list.dart

@@ -81,7 +81,7 @@ class _SubscriptionListPageState extends State<SubscriptionListPage> with PerAcc
     unpinned.sortBy((subscription) => subscription.name.toLowerCase());
 
     return Scaffold(
-      appBar: AppBar(title: const Text("Streams")),
+      appBar: AppBar(title: const Text("Channels")),
       body: SafeArea(
         // Don't pad the bottom here; we want the list content to do that.
         bottom: false,
@@ -115,7 +115,7 @@ class _NoSubscriptionsItem extends StatelessWidget {
     return SliverToBoxAdapter(
       child: Padding(
         padding: const EdgeInsets.all(10),
-        child: Text("No streams found",
+        child: Text("No channels found",
           textAlign: TextAlign.center,
           style: TextStyle(
             // TODO(#95) need dark-theme color

test/notifications/display_test.dart

@@ -166,7 +166,7 @@ void main() {
       final stream = eg.stream();
       final message = eg.streamMessage(stream: stream);
       await checkNotifications(async, messageFcmMessage(message, streamName: null),
-        expectedTitle: '(unknown stream) > ${message.subject}',
+        expectedTitle: '(unknown channel) > ${message.subject}',
         expectedTagComponent: 'stream:${message.streamId}:${message.subject}');
     }));