However, the highlighting of symbol is correct. symbol is a core function. Not a class. So the code in the screenshot will likely not work correctly.
user=> (defn ^symbol foo  'x)
user=> (.toString (foo))
CompilerException java.lang.IllegalArgumentException: Unable to resolve classname: clojure.core$symbol@73eb904d, compiling:(NO_SOURCE_PATH:4)
user=> (defn ^clojure.lang.Symbol bar  'x)
user=> (.toString (bar))
In general I would recommend to not use type hints at all. They are only needed when you use Java interop directly. And even then they could be left out if performance was not an issue. Otherwise you tie your code needlessly to specific classes. For example CharSequence works fine on the JVM, but maybe not on the CLR while the code would work perfectly fine on both platforms.