bookdown 0.48

• Fixed html_document2() breaking Plotly (and other htmlwidgets) in self-contained mode on Windows, where a ^Z (\x1a) byte embedded in JavaScript string literals (e.g., the PNG signature) was treated as end-of-file by readLines() on a text-mode connection, truncating the output file. The output file is now read with xfun::read_utf8(binary = TRUE) on Windows (thanks, @dmurdoch, #1523).