Minor correction in documentation

[ArashPartow]

In the documentation, should mmap1 be renamed to shared_mmap1 or vice versa

mio::shared_mmap_source shared_mmap1("path", offset, size_to_map);
mio::shared_mmap_source shared_mmap2(std::move(mmap1)); // or use operator=
mio::shared_mmap_source shared_mmap3(std::make_shared<mio::mmap_source>(mmap1)); // or use operator=
mio::shared_mmap_source shared_mmap4;
shared_mmap4.map("path", offset, size_to_map, error);

[wissem01chiha]

Hi, @ArashPartow , Thanks very much, we have continued the work here mio, feel free open issues, we will try to address any concerns as best as we can.