clang-format: do not accept version above 19.x

This gives me different formatting on latest version available in Debian. So
disabling for now.

tests/hghave.py

@@ -624,12 +624,13 def has_pylint():
     return matchoutput("pylint --help", br"[Uu]sage:[ ]+pylint", True)
 
 
-@check("clang-format", "clang-format C code formatter (>= 11)")
+@check("clang-format", "clang-format C code formatter (11 <= … < 19)")
 def has_clang_format():
     m = matchoutput('clang-format --version', br'clang-format version (\d+)')
-    # style changed somewhere between 10.x and 11.x
+    # style changed somewhere between 10.x and 11.x and after 19.
     if m:
-        return int(m.group(1)) >= 11
+        major_version = int(m.group(1))
+        return 11 <= major_version < 19
     # Assist Googler contributors, they have a centrally-maintained version of
     # clang-format that is generally very fresh, but unlike most builds (both
     # official and unofficial), it does *not* include a version number.