fix gcc-14 warnings

[huangminghuang]

This PR fixes the following warnings in gcc 14:

[build] ~/is_utf8/src/is_utf8.cpp:2571:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  2571 |   is_utf8_really_inline simd8<bool>() : base8() {}
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:2571:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:2572:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  2572 |   is_utf8_really_inline simd8<bool>(const __m256i _value)
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:2572:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:2575:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  2575 |   is_utf8_really_inline simd8<bool>(bool _value) : base8<bool>(splat(_value)) {}
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:2575:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3001:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3001 |   is_utf8_really_inline simd16<bool>() : base16() {}
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:3001:37: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3002:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3002 |   is_utf8_really_inline simd16<bool>(const __m256i _value)
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:3002:37: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3005:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3005 |   is_utf8_really_inline simd16<bool>(bool _value)
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:3005:37: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3552:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3552 |   is_utf8_really_inline simd8<bool>() : base8() {}
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:3552:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3553:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3553 |   is_utf8_really_inline simd8<bool>(const __m128i _value)
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:3553:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:3556:36: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  3556 |   is_utf8_really_inline simd8<bool>(bool _value) : base8<bool>(splat(_value)) {}
[build]       |                                    ^
[build] ~/is_utf8/src/is_utf8.cpp:3556:36: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:4068:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  4068 |   is_utf8_really_inline simd16<bool>() : base16() {}
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:4068:37: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:4069:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  4069 |   is_utf8_really_inline simd16<bool>(const __m128i _value)
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:4069:37: note: remove the ‘< >’
[build] ~/is_utf8/src/is_utf8.cpp:4072:37: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
[build]  4072 |   is_utf8_really_inline simd16<bool>(bool _value)
[build]       |                                     ^
[build] ~/is_utf8/src/is_utf8.cpp:4072:37: note: remove the ‘< >’

[lemire]

Running tests.