docs: Update CZO links from stream to channel in docs and comments.

Updates all the https://chat.zulip.org/#narrow/stream/ links in the
docs and comments to use the new /channel/ path. All these links are
for documentation/reference purposes only and thus, can be bulk-updated.

This commit is a part of the effort to rename stream to channel.

docs/outreach/apply.md

@@ -67,14 +67,14 @@ We recommend taking the following steps before diving into the issue tracker:
 - Join the [Zulip development
   community](https://zulip.com/development-community/), and introduce yourself
   in the channel for the program you are participating in
-  ([#GSoC](https://chat.zulip.org/#narrow/stream/14-GSoC) or
-  [#Outreachy](https://chat.zulip.org/#narrow/stream/391-Outreachy)). Before you
+  ([#GSoC](https://chat.zulip.org/#narrow/channel/14-GSoC) or
+  [#Outreachy](https://chat.zulip.org/#narrow/channel/391-Outreachy)). Before you
   jump in, be sure to review the [Zulip community
   norms](https://zulip.com/development-community/).
 
 - Follow our instructions to [install the development
   environment](../development/overview.md), getting help in [#provision
-  help](https://chat.zulip.org/#narrow/stream/21-provision-help) if needed.
+  help](https://chat.zulip.org/#narrow/channel/21-provision-help) if needed.
 
 - Familiarize yourself with [using the development
   environment](../development/using.md).
@@ -87,7 +87,7 @@ As you are getting started on your first pull request:
 
 - Read the [Zulip guide to Git](../git/overview.md). It's especially important
   to master using `git rebase`, so that you can restructure your commits. You can
-  get help in [#git help](https://chat.zulip.org/#narrow/stream/44-git-help) if
+  get help in [#git help](https://chat.zulip.org/#narrow/channel/44-git-help) if
   you get stuck.
 
 - To make it easier to structure your PRs well, we recommend installing a
@@ -182,8 +182,8 @@ give you feedback and help you improve your proposal.
 
 - Please post a link to your draft in the Zulip development community
   channel dedicated to your program (e.g.,
-  [#GSoC](https://chat.zulip.org/#narrow/stream/14-GSoC) or
-  [#Outreachy](https://chat.zulip.org/#narrow/stream/391-Outreachy)). Use
+  [#GSoC](https://chat.zulip.org/#narrow/channel/14-GSoC) or
+  [#Outreachy](https://chat.zulip.org/#narrow/channel/391-Outreachy)). Use
   `Your name - project proposal` as the topic.
 
 - We recommend linking to a draft in an app that works in the browser and allows

docs/outreach/experience.md

@@ -103,8 +103,8 @@ to ask your questions effectively.
 
 A check-in is a regular update that you post in the Zulip development community.
 You can find many examples in the
-[#checkins](https://chat.zulip.org/#narrow/stream/65-checkins) and
-[#GSoC](https://chat.zulip.org/#narrow/stream/14-GSoC) channels.
+[#checkins](https://chat.zulip.org/#narrow/channel/65-checkins) and
+[#GSoC](https://chat.zulip.org/#narrow/channel/14-GSoC) channels.
 
 - **Frequency**: _Regular check-ins are a required for all program
   participants._ If you are working 20+ hours per week, post a check-in at least
@@ -113,8 +113,8 @@ You can find many examples in the
 
 - **Where to post**: Unless your mentor or program administrator requests
   otherwise, post your check-ins in the channel for your program
-  (e.g., [#GSoC](https://chat.zulip.org/#narrow/stream/14-GSoC) or
-  [#Outreachy](https://chat.zulip.org/#narrow/stream/391-Outreachy)), using your
+  (e.g., [#GSoC](https://chat.zulip.org/#narrow/channel/14-GSoC) or
+  [#Outreachy](https://chat.zulip.org/#narrow/channel/391-Outreachy)), using your
   name as the topic.
 
 - **What to include** in each check-in:

docs/outreach/gsoc.md

@@ -129,7 +129,7 @@ Django, TypeScript/JavaScript, and CSS.
 
   Experts: Zixuan James Li, Evy Kassirer, Anders Kaseorg
 
-[typescript-migration]: https://chat.zulip.org/#narrow/stream/6-frontend/topic/typescript.20migration
+[typescript-migration]: https://chat.zulip.org/#narrow/channel/6-frontend/topic/typescript.20migration
 
 - Migrate server's Python codebase from the legacy
   `@has_request_variables` decorator to the new `@typed_endpoint`
@@ -415,9 +415,9 @@ Experts: Greg Price, Chris Bobbe
   experience with Android or iOS may also be helpful but is not
   necessary.
 
-[flutter-why]: https://chat.zulip.org/#narrow/stream/2-general/topic/Flutter/near/1582367
-[flutter-beta]: https://chat.zulip.org/#narrow/stream/2-general/topic/Flutter/near/1708728
+[flutter-why]: https://chat.zulip.org/#narrow/channel/2-general/topic/Flutter/near/1582367
+[flutter-beta]: https://chat.zulip.org/#narrow/channel/2-general/topic/Flutter/near/1708728
 [flutter-board]: https://github.com/orgs/zulip/projects/5/views/4
 [flutter-milestone-launch]: https://github.com/zulip/zulip-flutter/milestone/3
-[flutter-upstream-summary]: https://chat.zulip.org/#narrow/stream/2-general/topic/Flutter/near/1524757
+[flutter-upstream-summary]: https://chat.zulip.org/#narrow/channel/2-general/topic/Flutter/near/1524757
 [flutter-upstream-autocomplete]: https://github.com/flutter/flutter/pull/129802