Highlighting for fn[x] (without space) doesn't work

[naartjie]

Description

The highlighting for an anonymous function definition such as (fn[x] ) (without a space between fn and [x]) should pick up that it's a special form as well as tokenize the fn and the [x] parts separately, as this is valid Clojure, and right now the highlighting shows fn[x] as a single token, this can be confusing to beginners such as myself.

Steps to Reproduce

1. Open up a new file, called test.clj (make sure the syntax is set to Clojure)
2. type (fn[x] x)
3. note the highlighting

Expected behavior:

fn and [x] to appear in different colors (and fn to come up with a different color as other special forms), to make it obvious they are different tokens.

Actual behavior:

fn[x] appears as a single atomic unit.

Reproduces how often:

Always

Versions

languange-clojure 0.22.1
Atom 1.13.0