title: Make bold text in HTML output R shiny
body: <p>Reproducible example:</p>
  
  <pre><code>require(shiny)
  runApp(list(ui = pageWithSidebar(
  headerPanel("Example"),
    sidebarPanel(
      sliderInput("index", 
                  label = "Select a number",
                  min = 1,
                  max = 4,
                  step = 1,
                  value = 2)),
    mainPanel(
    htmlOutput("text")
    )),
  server = function(input, output) {
    output$text &lt;- renderUI({
      HTML(paste(c("banana","raccoon","duck","grapefruit")))
    })
  }
  ))
  </code></pre>
  
  <p>I would like to have the word corresponding to index ("raccoon" in the default) displayed in <strong>bold</strong> and the other words in normal font.</p>
  
  <p>If I do:</p>
  
  <pre><code>HTML(
  &lt;b&gt;paste(c("banana","raccoon","duck","grapefruit")[input$index])&lt;\b&gt;,
  paste(c("banana","raccoon","duck","grapefruit")[setdiff(1:4,input$index)])
  )
  </code></pre>
  
  <p>I receive an error (<code>&lt;</code> is not recognized)...</p>