Rollup merge of rust-lang#24948 - derhuerst:patch-1, r=steveklabnik

I've written a small [EditorConfig](http://editorconfig.org) file for Rust development.

Author: steveklabnik

src/etc/CONFIGS.md

@@ -1,10 +1,16 @@
 # Configs
 
-Here are some links to repos with configs which ease the use of rust:
+These are some links to repos with configs which ease the use of rust.
+
+## Officially Maintained Configs
 
 * [rust.vim](https://github.com/rust-lang/rust.vim)
 * [emacs rust-mode](https://github.com/rust-lang/rust-mode)
 * [gedit-config](https://github.com/rust-lang/gedit-config)
 * [kate-config](https://github.com/rust-lang/kate-config)
 * [nano-config](https://github.com/rust-lang/nano-config)
 * [zsh-config](https://github.com/rust-lang/zsh-config)
+
+## Community-maintained Configs
+
+* [.editorconfig](https://gist.github.com/derhuerst/c9d1b9309e308d9851fa) ([what is this?](http://editorconfig.org/))