Update README

Author: maxkapur

README.md

@@ -3,10 +3,17 @@
 A Python script to idempotently download, extract, and locally serve a mirror of
 [docs.python.org](https://docs.python.org/).
 
-**Installation/usage:** It only uses the standard library, so you can just run
-`./fetch_python_docs.py --serve` in your shell, or omit `--serve` to only
-download.
+## Installation and usage
 
-**Platforms?** Assumes Linux with `curl` and `tar` available for now.
+The script uses only the standard library and `requests`, so in most
+environments (e.g. Ubuntu) you can just run the script in your shell:
 
-**Why not use `pydoc -b`?** The color scheme.
+```
+./fetch_python_docs.py --serve
+```
+
+Omit `--serve` to only download and extract.
+
+## Why not just use `pydoc -b`?
+
+The color scheme.