How to disable formatting of fractions in tbl_summary?

The issue can be broken down to this:

rstudio/markdown < 2.0

> gt:::markdowntolatex(text = "5/6", mdengine = "markdown")
[1] "⅚"
> packageVersion("markdown")
[1] ‘1.13’

> markdown:::pants
       1/2        1/3        2/3        1/4        3/4        1/5        2/5        3/5 
"½" "⅓" "⅔" "¼" "¾" "⅕" "⅖" "⅗" 
       4/5        1/6        5/6        1/8        3/8        5/8        7/8        1/7 
"⅘" "⅙" "⅚" "⅛" "⅜" "⅝" "⅞"  "⅐" 
       1/9       1/10        (c)        (r)       (tm) 
 "⅑"  "⅒"   "©"    "®"  "™" 

In markdown::markdownoptions() is a smartypants option enabled which later causes the conversion which you see in the final table.

What works for me in order to circumvent this is to use the HTML code for the forward slash:

gt:::markdowntolatex(text = "5/6", mdengine = "markdown")
[1] "5/6"

> gt:::markdowntolatex(text = "5/6", mdengine = "markdown")
[1] "5/6"
> packageVersion("markdown")
[1] ‘2.0’

The reason is as follows: The markdown package is now superseded by litedown and therefore, several markdown functions are now only wrapper functions for litedown ones. In particular, markdown::markdownoptions only calls litedown under the hood:

> markdown::markdownoptions
function () 
litedown::markdownoptions()

# options disabled by default
x2 = c(
  'toc', 'hardbreaks', 'tagfilter', 'numbersections', 'cleveref', 'offline',
  'smartypants'
)

(although litedown:::pants and litedown:::smartypants are available), whereas markdown up to 1.13 had:

# options enabled by default
x1 = c(
  'smart', 'smartypants', 'embedresources', 'jsmath', 'jshighlight',
  'superscript', 'subscript', 'latexmath', 'autoidentifiers',
  setdiff(commonmark::listextensions(), 'tagfilter')
)