PrismSettings: Switch PRISM_LTL2DA_SYNTAX to CHOICE_TYPE

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@10246 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/prism/PrismSettings.java

@@ -311,7 +311,7 @@ public class PrismSettings implements Observer
 			{ STRING_TYPE,		PRISM_LTL2DA_TOOL,						"Use external LTL->DA tool",		"4.2.1",			"",		null,
 																			"If non-empty, the path to the executable for the external LTL->DA tool."},
 
-			{ STRING_TYPE,		PRISM_LTL2DA_SYNTAX,					"LTL syntax for external LTL->DA tool",		"4.2.1",			"LBT",		"LBT,Spin,Spot,Rabinizer",
+			{ CHOICE_TYPE,		PRISM_LTL2DA_SYNTAX,					"LTL syntax for external LTL->DA tool",		"4.2.1",			"LBT",		"LBT,Spin,Spot,Rabinizer",
 																			"The syntax for LTL formulas passed to the external LTL->DA tool."},
 
 			// PARAMETRIC MODEL CHECKING