title: Page number for references with pdf_book is final reference page, not first
body: <p>In the file _output.yml, I have</p>
  <pre><code>bookdown::pdf_book:
    includes:
      in_header: preamble.tex
    toc_depth: 2
    latex_engine: xelatex
    citation_package: natbib
    toc_bib: true
    keep_tex: yes
  </code></pre>
  <p>The toc page numbers are all correct, except for the page number
  for what I have called References rather than Bibliography,
  which is 84 where it should be 81.</p>
  <p>(I used</p>
  <pre><code>\renewcommand{\bibname}{References}
  </code></pre>
  <p>in index.Rmd to change the name to References, but have
  checked that this make no difference to the number in the toc)</p>
  <p>Added August 19 2021:
  It turns out that if I go back and rerun &quot;Build Book&quot; after running it with citation_package: natbib removed, then rerun with citation_package: natbib added back in again, the references appear
  thus (. . . for references after the first), and the page number in the table of contents is correct.</p>
  <pre><code>\begin{CSLReferences}{0}{0}
  \leavevmode\hypertarget{ref-r2_begley_2013}{}%
  Begley, C. G. 2013. {``Reproducibility: Six Red Flags for Suspect Work.''} \emph{Nature} 497 (7450): 433--34. \url{https://doi.org/10.1038/497433a}.
  . . .
  \end{CSLReferences}
  </code></pre>
  <p>and the page reference is correct.</p>