tests: correctly match clang-format version >= 10

The previous regex only matched the first digit, so "clang-format version
10.0.0" was recognized as version 1.

tests/hghave.py

@@ -591,7 +591,7 b' def has_pylint():'
 
 @check("clang-format", "clang-format C code formatter")
 def has_clang_format():
-    m = matchoutput('clang-format --version', br'clang-format version (\d)')
+    m = matchoutput('clang-format --version', br'clang-format version (\d*)')
     # style changed somewhere between 4.x and 6.x
     return m and int(m.group(1)) >= 6