Fix invalid escape sequence in utils, minor cleanup in python script (v…

…alkey-io#948)

According to the Python document[1], any invalid escape sequences in
string literals now generate a DeprecationWarning (SyntaxWarning as of
3.12) and in the future this will become a SyntaxError.

This Change uses Python’s raw string notation for regular expression
patterns to avoid it.

[1]: https://docs.python.org/3.10/library/re.html

Signed-off-by: haoqixu <hq.xu0o0@gmail.com>

utils/generate-unit-test-header.py

@@ -4,7 +4,7 @@
 
 UNIT_DIR = os.path.abspath(os.path.dirname(os.path.abspath(__file__)) + '/../src/unit')
 TEST_FILE = UNIT_DIR + '/test_files.h'
-TEST_PROTOTYPE = '(int (test_[a-zA-Z0-9_]*)\(.*\)).*{'
+TEST_PROTOTYPE = r'(int (test_[a-zA-Z0-9_]*)\(.*\)).*{'
 
 if __name__ == '__main__':
     with open(TEST_FILE, 'w') as output: