doc-src/IsarImplementation/Thy/ROOT.ML

slightly more standard data merge: Symtax.merge (K true) avoids equality on abstract type Pretty.T and gracefully accepts overriding, Symtab.join prefers first entry as usual;

use_thys [
  "Integration",
  "Isar",
  "Local_Theory",
  "Logic",
  "ML",
  "Prelim",
  "Proof",
  "Syntax",
  "Tactic"
];