\copybrief adds a link to the copied function in the detailed description

[anarthal]

When \copybrief is used, the brief description is copied, but a spurious reference to the copied entity is inserted in the detailed description. For instance:

namespace boost::mysql {

/**
 * \brief Some function.
 * \details Some details.
 */
void f();

/**
 * \copybrief f
 * \details Additional details.
 */
void g();

}  // namespace boost::mysql

Renders:

$> mrdocs --version
MrDocs
    C++ Documentation Tool
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    build: 93d5d102c39b093d402ae3f95302fd734c8de616
    built with LLVM 20.0.0git