Remove StringLiteral(const char*) ctor to fix ambiguity on Clang/GCC

The const char* constructor was ambiguous with const char(&)[N] for
string literals like "". Replace its only usage in transform_case.hpp
with an intermediate std::array copy.

Author: Centimo

include/rfl/internal/StringLiteral.hpp

@@ -24,10 +24,6 @@ struct StringLiteral {
     std::copy_n(_str, N, std::data(arr_));
   }
 
-  explicit constexpr StringLiteral(const char* _data) {
-    std::copy_n(_data, N, std::data(arr_));
-  }
-
 
   /// Returns the value as a string.
   std::string str() const { return std::string(string_view()); }

include/rfl/internal/transform_case.hpp

@@ -46,7 +46,9 @@ consteval auto transform_camel_case() {
   }
 
   if constexpr (!src.empty() && is_upper(src[0])) {
-    return StringLiteral<len>(result.data() + 1);
+    auto trimmed = std::array<char, len>{};
+    std::copy_n(result.data() + 1, len - 1, trimmed.data());
+    return StringLiteral<len>(trimmed);
   }
   else {
     return StringLiteral<len + 1>(result);