Unreserve 'get', 'sort', 'limit', 'offset', and 'group' for type labels

Author: haikalpribadi

grammar/Graql.g4

@@ -59,7 +59,7 @@ query_match_group_agg :   query_match   match_group       match_aggregate  ;
 
 modifiers             : ( filter';' )? ( sort';' )? ( offset';' )? ( limit';' )?;
 
-filter                :   FILTER      VAR_  ( ',' VAR_ )*   ;
+filter                :   GET         VAR_  ( ',' VAR_ )*   ;
 sort                  :   SORT        VAR_        ORDER_?   ;
 offset                :   OFFSET      LONG_                 ;
 limit                 :   LIMIT       LONG_                 ;
@@ -243,6 +243,7 @@ regex                 :   STRING_         ;
 
 unreserved            : VALUE
                       | MIN | MAX| MEDIAN | MEAN | STD | SUM | COUNT
+                      | GET | SORT | LIMIT | OFFSET | GROUP
                       | PATH | CLUSTER | FROM | TO | OF | IN
                       | DEGREE | K_CORE | CONNECTED_COMPONENT
                       | MIN_K | K | CONTAINS | SIZE | WHERE
@@ -252,7 +253,7 @@ unreserved            : VALUE
 
 // QUERY COMMAND KEYWORDS
 
-MATCH           : 'match'       ;   FILTER          : 'get'         ;
+MATCH           : 'match'       ;   GET             : 'get'         ;
 DEFINE          : 'define'      ;   UNDEFINE        : 'undefine'    ;
 INSERT          : 'insert'      ;   DELETE          : 'delete'      ;
 COMPUTE         : 'compute'     ;