fix(core): don't change unicode characters

tests/test_naming.py

@@ -9,8 +9,10 @@ def req(**kw):
     return SimpleNamespace(**base)
 
 
-def test_sanitize_removes_forbidden_chars():
-    assert sanitize('A<b>:c/d\\e|f?g*h"') == "Abcdefgh"
+def test_sanitize_replaces_forbidden_chars():
+    assert sanitize("Die drei ???") == "Die drei ？？？"
+    assert sanitize("a/b") == "a⧸b"
+    assert "\x01" not in sanitize("a\x01b")
 
 
 def test_ebook_template():