Changed name of fn to_keytree() to keytree().

Dependencies

• [2] K5VHGRGG Add serialization.

Change contents

• replacement in src/serialize.rs at line 4
  [2.55]→[2.55:98](∅→∅)
  − fn to_keytree(&self) -> KeyTreeString;
  [2.55]

  [2.98]
  + fn keytree(&self) -> KeyTreeString;