OpenSystemsDevelopment / qpdf

`basic_string<unsigned char>` implies use of
`char_traits<unsigned char>`.

This char_traits specialization is not standard C++, and will be
removed from LibC++ as of LLVM 18. To ensure continued LibC++
compatibility it needs to be removed.

There are two possible replacements here: `std::string` (e.g.
`std::basic_string<char>`), or `std::vector<unsigned char>`.

I have opted for vector since this code is dealing with a binary
buffer; though probably either way is fine (why does C++ even have
strings anyway??).

https://github.com/qpdf/qpdf/issues/1024

Fix typo in manual

Fix QPDFObjectHandle::disconnect (partially fixes #1011)

Fix formatting in library.rst

Split QPDF::readObject into readTrailer, readObject and readObjectInStream

 Add new private method QPDF::insertReconstructedXrefEntry

Add doxygen files to .gitignore

Add content table to TODO file

Bump version to 11.5.0

Ensure copied annotations are fixed (fixes #600)

 Add new Buffer method copy and deprecate copy constructor / assignment operator

Future

Also fix accidental Buffer copy in Pl_LZWDecoder::addToTable.

Also remove trailing whitespace