Improve getting started Coder CTA (#5752)

* Improve getting started Coder CTA

This wasn't very standout-ish before, and I think it's
wise for us to experiment with directing users to Coder.

* Update nix flake

* Update diff

* Add advert to code-server install

* Fix patch to reset columns if getting started is disabled

* Update text for advert

install.sh

@@ -131,6 +131,11 @@ Or, if you don't want/need a background service you can run:
 EOF
 }
 
+echo_coder_postinstall() {
+  echoh
+  echoh "Deploy code-server for your team with Coder: https://github.com/coder/coder"
+}
+
 main() {
   if [ "${TRACE-}" ]; then
     set -x
@@ -243,6 +248,7 @@ main() {
   if [ "$METHOD" = standalone ]; then
     if has_standalone; then
       install_standalone
+      echo_coder_postinstall
       exit 0
     else
       echoerr "There are no standalone releases for $ARCH"
@@ -286,6 +292,8 @@ main() {
       npm_fallback install_standalone
       ;;
   esac
+
+  echo_coder_postinstall
 }
 
 parse_arg() {