fix: shorten Codespaces welcome text

It was too long and didn't appear front and center.  This is just
slightly better UX and diverts your attention to the most important
thing (setup steps).

Author: pwnage101

.devcontainer/welcome.txt

@@ -18,20 +18,7 @@ Initial Setup
 
    https://marketplace.visualstudio.com/items/?itemName=GitHub.codespaces
 
-Usage
-=====
-
-Start your day by connecting to this workspace from VS Code and start up
-services from a terminal:
-
-  make dev.up
-
-Important directories:
-
-* /workspaces/devstack - This is the main devstack repository.
-* /workspaces/devstack/edx-repos/* - Individual edx service repository clones.
-
 More Info
 =========
 
-* https://2u-internal.atlassian.net/wiki/spaces/SOL/pages/2003370007/Devstack+on+Codespaces+Guide
+https://2u-internal.atlassian.net/wiki/spaces/ENG/pages/2003370007/Devstack+on+Codespaces+Guide