Replace most uses of typedef with using for type aliasing

src/probabilistic/BitVector.h

@@ -21,9 +21,9 @@ namespace zeek::probabilistic::detail
 class BitVector
 	{
 public:
-	typedef uint64_t block_type;
-	typedef size_t size_type;
-	typedef bool const_reference;
+	using block_type = uint64_t;
+	using size_type = size_t;
+	using const_reference = bool;
 
 	static size_type npos;
 	static block_type bits_per_block;

src/probabilistic/CounterVector.h

@@ -25,8 +25,8 @@ class BitVector;
 class CounterVector
 	{
 public:
-	typedef size_t size_type;
-	typedef uint64_t count_type;
+	using size_type = size_t;
+	using count_type = uint64_t;
 
 	/**
 	 * Constructs a counter vector having cells of a given width.

src/probabilistic/Hasher.h

@@ -29,8 +29,8 @@ enum HasherType
 class Hasher
 	{
 public:
-	typedef zeek::detail::hash_t digest;
-	typedef std::vector<digest> digest_vector;
+	using digest = zeek::detail::hash_t;
+	using digest_vector = std::vector<digest>;
 	struct seed_t
 		{
 		// actually HH_U64, which has the same type