Add KUKA Robot Language (KRL) Syntax to Prism

Language
Kuka Robot Language (KRL) is used to control KUKA robots. It is similar to Pascal.

Additional resources
There is already an implementation for Visual Studio Code:
KUKA KRL (KUKA Robot Language) support in Visual Studio Code

An this is the syntax file from the same repo:
https://github.com/d4nuu8/language-kuka-krl/blob/master/syntaxes/krl.tmLanguage.json

An official reference guide can be found here:
Reference Guide v4.1

Example code

&ACCESS RVP  
&REL 87  
&COMMENT HANDLER on external automatic  
DEF  CELL ( )  
  ;FOLD INIT  
  DECL CHAR DMY[3]  
  DMY[]="---"  
        
  ;ENDFOLD (INIT)  
      
  IF ($T1) OR ($T2) THEN  
     HALT  
  ENDIF    

  ; function call
  Gripper_Test()  
  
  ; interrupt declaration
     INTERRUPT DECL 4 WHEN $FLAG[1] DO IRQ4_Homing( )  
     
   CONTINUE  
   
   SWITCH(MatrizeNum)       
   CASE 1  
      Offset=4    
   CASE 3        
      Offset=8  
   DEFAULT  
      LOOP  
         HALT  
      ENDLOOP  
   ENDSWITCH  
   
  LOOP  
      ; Comment 
  ENDLOOP  
    
END

Start by reviewing the linked KUKA KRL VS Code implementation and its syntaxes/krl.tmLanguage.json, then compare them with the KRL reference guide and example code in this issue. Done means Prism can highlight the shown KRL constructs, including directives, declarations, comments, control flow, and function calls.