README: edit headers

README.md

@@ -2,19 +2,19 @@
 
 > The ancient DOOM fire animation in the terminal!
 
-### what?
+## what?
 `fire` is a remake of the PSX DOOM fire animation in the terminal,
 as seen in the [ly](https://github.com/cylgom/ly) display manager.
 It's described nicely by Fabien Sanglard on his
 [blog](https://fabiensanglard.net/doom_fire_psx/index.html).
 
-### where?
-#### supported platforms
+## where?
+### supported platforms
 - Linux (musl/glibc) (*tested and supported*)
 - Windows (*should work, but not tested*)
 - (Dragonfly|Net|Free|Open)BSD: (*not tested, might work*)
 
-#### building from source
+### building from source
 You will need:
 - `git`
 - a c99 compiler (gcc or clang)
@@ -40,7 +40,7 @@ Uninstall, if you wish:
 # rm -f /usr/bin/fire
 ```
 
-### how?
+## how?
 simply run `./fire` (or `fire`, if you installed) and enjoy.
 ```
 $ fire
@@ -49,11 +49,11 @@ $ fire
 ### why?
 I'm bored
 
-### credits
+## credits
 Thanks to @cylgom, for inspiring me to make this project.
 More thanks to @cylgom, from whose repositories I sto^Hborrowed a lot
 of stuff :)
 
-### license
+## license
 This project is licensed under the MIT license. View the LICENSE.md file
 for more information.