7074853: TransparentRuler demos Readme should mention the correct jar file name

Reviewed-by: rupashka

src/share/demo/jfc/TransparentRuler/README.txt

 
 To run the Ruler demo:
 
-  java -jar Ruler.jar
+  java -jar TransparentRuler.jar
 
 These instructions assume that this installation's version of the java
 command is in your path.  If it isn't, then you should either
 specify the complete path to the java command or update your
 PATH environment variable as described in the installation
 instructions for the Java(TM) SE Development Kit.
-
-KNOWN ISSUES:
-Context menu is clipped with the window shape. The issues are:
-CR 7027486 JPopupMenu doesn't take window shape into account