Use write_provenance_header() more

Author: gvanrossum

Tools/cases_generator/generate_cases.py

@@ -1179,10 +1179,7 @@ def write_instructions(self) -> None:
             # Create formatter
             self.out = Formatter(f, 8, self.emit_line_directives)
 
-            # Write provenance header
-            self.out.write_raw(f"{self.out.comment} This file is generated by {THIS}\n")
-            self.out.write_raw(self.from_source_files())
-            self.out.write_raw(f"{self.out.comment} Do not edit!\n")
+            self.write_provenance_header()
 
             # Write and count instructions of all kinds
             n_instrs = 0