scripted-diff: modernize outdated trait patterns - values

See https://en.cppreference.com/w/cpp/types/is_enum for more details.

-BEGIN VERIFY SCRIPT-
sed -i -E 's/(std::[a-z_]+)(<[^<>]+>)::value\b/\1_v\2/g' $(git grep -l '::value' ./src ':(exclude)src/bench/nanobench.h' ':(exclude)src/minisketch' ':(exclude)src/span.h')
-END VERIFY SCRIPT-

src/util/strencodings.cpp

@@ -204,7 +204,7 @@ namespace {
 template <typename T>
 bool ParseIntegral(std::string_view str, T* out)
 {
-    static_assert(std::is_integral<T>::value);
+    static_assert(std::is_integral_v<T>);
     // Replicate the exact behavior of strtol/strtoll/strtoul/strtoull when
     // handling leading +/- for backwards compatibility.
     if (str.length() >= 2 && str[0] == '+' && str[1] == '-') {