Line names in grid-template-columns and grid-template-rows are not parsed

[TastyPi]

Example:

.example-grid {
  display: grid;
  grid-template-columns: [start] auto [middle] 1fr [end];
  grid-template-rows: [top] auto [middle] 1fr [bottom];
}

Gives the errors:

[
    Message:error on line 3, column 26: Expecting a positive number  
    ╷  
  3 │   grid-template-columns: [start] auto [middle] 1fr [end];  
    │                          ^^^^^^  
    ╵,
    Message:error on line 3, column 39: Expecting a positive number  
    ╷  
  3 │   grid-template-columns: [start] auto [middle] 1fr [end];  
    │                                       ^^^^^^^  
    ╵,
    Message:error on line 3, column 52: Expecting a positive number  
    ╷  
  3 │   grid-template-columns: [start] auto [middle] 1fr [end];  
    │                                                    ^^^^  
    ╵,
    Message:error on line 4, column 23: Expecting a positive number  
    ╷  
  4 │   grid-template-rows: [top] auto [middle] 1fr [bottom];  
    │                       ^^^^  
    ╵,
    Message:error on line 4, column 34: Expecting a positive number  
    ╷  
  4 │   grid-template-rows: [top] auto [middle] 1fr [bottom];  
    │                                  ^^^^^^^  
    ╵,
    Message:error on line 4, column 47: Expecting a positive number  
    ╷  
  4 │   grid-template-rows: [top] auto [middle] 1fr [bottom];  
    │                                               ^^^^^^^  
    ╵
]

[kevmoo]

CC @leonsenft – we may be will to accept a pull request here, @TastyPi