anchor.diff:  <% end %>
   
   
  -<% function 'meta.function-exists($name)',
  +<% function 'meta.function-exists($name, $module: null)',
               'function-exists($name)',
               returns: 'boolean' do %>
     Returns whether a function named `$name` is defined, either as a built-in
     function or a user-defined function.
   
  -  <% example(autogen_css: false) do %>
  +  If `$module` is `null`, this returns the function named `$name` without a
  +  namespace (including [global built-in functions][]). Otherwise, `$module` must
  +  be a string matching the namespace of a [`@use` rule][] in the current file,
  +  in which case this returns the function in that module named `$name`.
  +
  +  <% example(autogen_css: false) do %>
  +    @use "sass:math";
  +
  +    @debug meta.function-exists("div", "math"); // true
       @debug meta.function-exists("scale-color"); // true
       @debug meta.function-exists("add"); // false
   
  
positive.code:     ===
      @debug meta.variable-exists("var1")  // false
  
      $var1: value 
      @debug meta.variable-exists("var1")  // true
  
      h1
  
negative.code:   Returns whether a [mixin][] named `$name` exists.
  
    [mixin]: ../at-rules/mixin
  
    If `$module` is `null`, this returns whether a mixin named `$name` without a
    namespace exists. Otherwise, `$module` must be a string matching the namespace
    of a [`@use` rule][] in the current file, in which case this returns whether
  