Vim PlantUML Syntax/Plugin/FTDetect
This is the PlantUML Syntax file from Anders Thøgersen.
Additionally, I've added a Plugin which sets the makeprg for generating. It assumes you have a script in the path named 'plantuml' which takes plantuml files as argument. You can define your own script file by settting g:plantuml_executable_script to something.
There is also an FTDetect file which looks for '@startuml' on the first line to set the plantuml filetype.