Typos "unkown"

[linuswagner]

There are four locations in Rascal, where someone wrote "unkown" instead of "unknown":

• src/org/rascalmpl/interpreter/utils/ReadEvalPrintDialogMessages.java (2x)
• src/org/rascalmpl/library/lang/smtlib2/Compiler.rsc
• src/org/rascalmpl/library/lang/smtlib2/command/response/Ast.rsc

Can they be replaced by the correct spelling or will this cause unwanted side-effects?

[jurgenvinju]

thanks @linuswagner ; please replace them? if there are "unkown" side-effects, probably a test would fail.