README - small changes

- Add link to jump to installation section
- Add link to jump to installing tab completion. Named this link "auto-complete" so that "auto" and "complete" (ending with an -e rather than -ion) would both show up when grepped/ ⌘+F

Why:

- Less intimidating to newcomers — I've just observed that friends/colleagues adopt tldr rather than cheat.sh soley because they didn't see the "get started" stuff up top. So they missed it.
- Faster to "just install it" when you know you're going to do that anyways. i.e. from a friend recommending. or on a new machine.

Author: floer32

README.md

@@ -15,7 +15,7 @@ What features should it have?
 * **Tutoring** — It should help you to learn the subject.
 * **Inconspicuous** — It should be possible to use it completely unnoticed.
 
-Such a thing exists.
+Such a thing exists! It's easy to [install](#installation) and there's even [auto-complete](#tab-completion).
 
 
 ## Features