Switch Expression/Rule Switch Enhancements and fixes

1. New hint to convert mixed case kind in Switch-Expression/Switch-Cases to rule kind cases (JDK-12 & above)
   
   hint  for converting mixed case type in Switch to rule kind cases.
   
   
   After implementing the error fix:
   
   
   Hint for converting mixed type in Switch expression to to rule kind cases.
   
   
   After implementing the error fix:
   
   
   
2. Formatting and correct re indentation of Switch-Expression and Rule Switch.
     switch-expression before formatting :
   
   switch-expression after formatting :
   
   switch-expression with rule cases before formatting.
       
3. Auto complete of enum case values in Switch-Expression
   
   
   
   

Bug-Fixes:

1. NETBEANS-1728: ClassCastException in Switch Expression
2. NETBEANS-1674: NPE thrown while formatting the switch expression