Updated TreeShaker's usage message.
@@ -23,8 +23,10 @@ where possible options include:\n\
-classpath <path> Specify where to find user class files.\n\
--tree-shaker-roots Specify a file that lists the public root classes and methods.\n\
-s, --sourcefilelist <file> Specify a file that lists the source files to be analyzed.\n\
- -encoding <encoding> Specify character encoding used by source files\n\
- -Xbootclasspath:<path> Boot path used to compile the input sources. (not the tool itself)\n\
+ -o, --output-file <file> Write output to file.
+ -encoding <encoding> Specify character encoding used by source files.\n\
+ -source <release> Provide source compatibility with specified release.
+ -Xbootclasspath:<path> Boot path used to compile the input sources (not the tool itself).\n\
-version Version information\n\
-Werror Treats all warning as errors.\n\
-h, --help Print this message.
