- formatted https://www.pantsbuild.org/docs/welcome-to-pants#what-is-pants to use a list when describing builds, rather than dense paragraph - added "ergonomics" as an explicit goal in that first section - reworded our guidance on the #welcome channel to make it be stronger at https://www.pantsbuild.org/docs/getting-help#slack - renamed "Concepts" to "Key concepts", with the hope that people will realize they should probably read it: https://www.pantsbuild.org/docs/concepts

I suspect we're taking too long to get to explaining what Pants really does, e.g. we don't show a screenshot until the second page "How does Pants work?" I suspect we should merge "Welcome to Pants!" with "How does Pants work"?

cc @happy-kitchen-89482 @busy-vase-39202