First stab at adding support for Rust.

lib/linguist/languages.yml

@@ -721,6 +721,12 @@ Ruby:
   - Thorfile
   - Gemfile
 
+Rust:
+  type: programming
+  extensions:
+  - .rs
+  - .rc
+
 SQL:
   type: data
   searchable: false

lib/linguist/mimes.yml

@@ -55,4 +55,5 @@ text/plain @cu,cxx
 text/x-nimrod @nim
 text/x-ocaml @ml,mli,mll,mly,sig,sml
 text/x-nemerle @n
+text/x-rust @rs,rc
 text/x-scheme @rkt,scm,sls,sps,ss