minify-js: Remove; everything has been migrated to Webpack.

min/sockjs-0.3.4.min.js is not used.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

docs/production/maintain-secure-upgrade.md

@@ -215,8 +215,8 @@ git_repo_url = https://github.com/zulip/zulip.git
 **Systems with limited RAM**: If you are running a minimal Zulip
   server with 2GB of RAM or less, the upgrade can fail due to the
   system running out of RAM running both the Zulip server and Zulip's
-  static asset build process (`tools/minify-js`, which calls
-  `webpack`, is usually the step that fails).  If you encounter this,
+  static asset build process (`tools/webpack`
+  is usually the step that fails).  If you encounter this,
   you can run `supervisorctl stop all` to shut down the Zulip server
   while you run the upgrade (this will, of course, add some downtime,
   which is part of we already recommend more RAM for organizations of

docs/subsystems/front-end-build-process.md

@@ -78,10 +78,6 @@ If you want to test minified files in development, look for the
 `PIPELINE_ENABLED =` line in `zproject/settings.py` and set it to `True`
 -- or just set `DEBUG = False`.
 
-Note that `static/html/5xx.html` will only render properly if
-minification is enabled, since they, by nature, hardcode the path
-`static/min/portico.css`.
-
 ## How it works in production
 
 You can learn a lot from reading about django-pipeline, but a few