title: RMarkdown: Floating TOC and TOC at beginning
body: <p>I was wondering if it is possible to have a floating table of contents and another one at the beginning of the document. My current front-matter looks like this:</p>
  
  <pre><code>---
  title: "TEST"
  author: brettljausn
  date: January 15, 2018
  output: 
    html_document:
      toc: true
      toc_float:
        toc_collapsed: true
      toc_depth: 3
      number_sections: true
      theme: lumen
  ---
  
  
  # Rest of the sample document: --------
  
  ```{r setup, include=FALSE}
  knitr::opts_chunk$set(echo = TRUE)
  ```
  
  # R Markdown
  
  This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see &lt;http://rmarkdown.rstudio.com&gt;.
  
  When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:
  
  ```{r cars}
  summary(cars)
  ```
  
  ## Including Plots
  
  You can also embed plots, for example:
  
  ```{r pressure, echo=FALSE}
  plot(pressure)
  ```
  
  Note that the `echo = FALSE` parameter was added to the code chunk to prevent printing of the R code that generated the plot.
  </code></pre>
  
  <p>I've tried adding another <code>toc: true</code>, but that just throws me an error message. Thanks in advance!</p>