Rendering markdown text

whichtip.Rmd

---
output:
  html_document:
    df_print: paged
runtime: shiny
---

```{r include = FALSE}
knitr::opts_chunk$set(echo = FALSE)
```

```{r}
library(shiny)

yml_info <- list(
    tip1 = list(tip = 'This is a [link](https://community.rstudio.com/).'),
    tip2 = list(tip = 'Here is an HTML <a href = "https://community.rstudio.com/">link</a>!'))

selectInput("whichtip", label = "Select puzzle:",
            choices = c("tip1", "tip2"))
                        
actionButton("tip", "Tip")

show_tip <- eventReactive(input$tip, {
    yml_info[[input$whichtip]]$tip
})
```

The text here does not render (click tip to see):
```{r results = "asis"}
renderUI(show_tip())
```

The text here does:  
```{r results = "asis"}
yml_info[["tip1"]]$tip
yml_info[["tip2"]]$tip
```

Screenshot: