title: How to change caption label names in a single document with Bookdown?
body: <p>I have created a <a href="https://bookdown.org/yihui/bookdown/a-single-document.html" rel="noreferrer">single document</a> with the Bookdown-package of R-Markdown that allows both html- and pdf-output. I would like to change the caption labels <code>Figure</code>, <code>Table</code> and <code>Table of Contents</code> into another language. Here's a minimal example:</p>
  
  <pre><code>---
  title: Dokument auf Deutsch
  output:
    bookdown::html_document2:
      toc: yes
    bookdown::pdf_document2:
      toc: yes
  ---
  
  # Erstes Kapitel
  
  Abbildung \@ref(fig:pressure) ist Deutsch.
  
  ```{r pressure, echo=FALSE, out.width = "80%", fig.pos='h', fig.cap="Deutsche Bildunterschrift"}
  plot(pressure)
  ```
  </code></pre>
  
  <p>Bookdown uses the English word 'Figure' for the figure caption prefix. When knitting to pdf_document2, Bookdown uses the English word 'Contents' for the toc. How to change these to 'Abbildung' and 'Inhalt'?</p>
  
  <p>I have read <a href="https://bookdown.org/yihui/bookdown/internationalization.html" rel="noreferrer">section 4.5 Internationalization</a> in the Bookdown manual. The author suggests to edit a configuration file <code>_bookdown.yml</code>, where one could change the label names. However, I can't find such a configuration file, my single Bookdown-document seems to be self-contained. Also, the example in section 4.5 doesn't indicate how to change the term for the toc.</p>
  
  <p>I found <a href="https://stackoverflow.com/questions/47173279/internationalization-r-knitr-figure-caption-label?rq=1">this answer</a> with the <code>\renewcommand</code>. This works for figures and tables when using <code>output:pdf_document2</code>, but not with <code>output:html_document2</code>. As a side issue, <code>\renewcommand{\contentsname}{Inhalt}</code> doesn't change 'Contents' into 'Inhalt' in the pdf-output. So <code>\renewcommand</code> is not an ideal workaround.</p>
  
  <p>I would actually like to use the original solution described in the above section 4.5 of the Bookdown manual. Where can I find this configuration file <code>_bookdown.yml</code> when I write a single Bookdown-document? Where in that file could I change the term for the toc? If I have to first create this configuration file, how exactly should I do that and how can I link it to my single Rmd-document?</p>