fix: `unit_symbol()` and `dimension_symbol()` returns now `std::basic… #2057

Job	Run time
Generate build matrix for Conan CI	6s
Apple Clang 15.2 C++20 fmtlib gsl-lite Debug	3m 14s
Apple Clang 15.2 C++23 fmtlib gsl-lite Release	3m 16s
Apple Clang 16.1 C++20 fmtlib gsl-lite Debug	2m 13s
Apple Clang 16.1 C++20 std::format gsl-lite Debug	2m 2s
Clang-16 (x86-64) C++20 fmtlib gsl-lite Debug	4m 57s
Clang-16 (x86-64) C++23 fmtlib none Debug	5m 6s
Clang-17 (x86-64) C++20 fmtlib none Debug	7m 13s
Clang-17 (x86-64) C++20 std::format gsl-lite Debug	6m 20s
Clang-18 (arm64) C++20 std::format gsl-lite Debug	3m 1s
Clang-18 (arm64) C++23 fmtlib none Release	3m 33s
Clang-18 (x86-64) C++20 fmtlib ms-gsl Release	7m 34s
Clang-18 (x86-64) C++20 std::format gsl-lite Debug	6m 47s
Clang-18 (x86-64) C++23 std::format none Debug	6m 32s
GCC-12 C++20 fmtlib gsl-lite Debug	5m 0s
GCC-12 C++23 fmtlib ms-gsl Release	4m 54s
GCC-13 C++20 std::format gsl-lite Debug	3m 50s
GCC-13 C++20 std::format none Release	3m 47s
GCC-14 C++20 fmtlib none Release	3m 42s
GCC-14 C++20 std::format gsl-lite Debug	3m 40s
MSVC 14.4 C++20 fmtlib ms-gsl Release	2m 4s
MSVC 14.4 C++20 std::format gsl-lite Debug	1m 30s
Promote Conan package	2m 50s
	1h 33m 11s

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