Update rsyntaxtextarea to version 2.5.3

(Until version 2.5.3 of RSyntaxTextArea is available on maven.imagej.net, this request should be ignored. :-) )

In the hopes of improving compatibility with Micro-Manager, as well as keeping dependencies up to date, I've created this patch series to update imagej-ui-swing to the latest version of the RSyntaxTextArea API. (2.5.3 was released on 30 June.)

The first patch is just a fixup to catch some missed token instance -> TokenType references. The next changes the version in the POM. The remaining three are minor fixes to API (probably they could've been rolled into one patch, but this works).