Semicolon Cleanup

1. Semicolons were required in the wrong spot.
2. Make semicolons "invisible" (from the tree-sitter perspective).

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

tree-sitter-p4/test/corpus/instantiations.txt

@@ -12,6 +12,5 @@ bool() main;
   )
   (identifier)
  ) 
- (semicolon)
 )