Infinite loop when computing semantic tokens for an ENV instruction with multiple embedded comments

[rcjsuen]

ENV a \
 b \
 # comment 
 # comment 
 c

let lib = require("dockerfile-language-service");
let service = lib.DockerfileLanguageServiceFactory.createLanguageService();
let content = "ENV a \\\n b \\\n # comment \n # comment \n c";
service.computeSemanticTokens(content);

The code above will create an infinite loop on RunKit.