--- a/src/Pure/System/isabelle_tool.scala Thu Mar 04 19:55:52 2021 +0100
+++ b/src/Pure/System/isabelle_tool.scala Thu Mar 04 21:04:27 2021 +0100
@@ -157,7 +157,7 @@
Start Isabelle TOOL with ARGS; pass "-?" for tool-specific help.
-Available tools:""" + tool_descriptions.mkString("\n ", "\n ", "\n")).usage
+Available tools:""" + tool_descriptions.mkString("\n ", "\n ", "\n")).usage()
case tool_name :: tool_args =>
find_external(tool_name) orElse find_internal(tool_name) match {
case Some(tool) => tool(tool_args)