Fix broken links

source/documentation/interpolation.html.md.erb

@@ -15,7 +15,7 @@ introduction: >
 * [Plain CSS `@import`s](at-rules/import#plain-css-imports)
 * [Quoted or unquoted strings](values/strings)
 * [Special functions](syntax/special-functions)
-* [Plain CSS function names](functions/css)
+* [Plain CSS function names](at-rules/function#plain-css-functions)
 * [Loud comments](syntax/comments)
 
 <% example do %>
@@ -147,5 +147,5 @@ them into style rules.
   strings, it's a lot clearer to use the [`string.unquote()` function][].
   Instead of `#{$string}`, write `string.unquote($string)`!
 
-  [`string.unquote()` function]: functions/string#unquote
+  [`string.unquote()` function]: modules/string#unquote
 <% end %>

source/documentation/modules.html.md.erb

@@ -75,7 +75,6 @@ Sass provides the following built-in modules:
 
 * The [`sass:meta` module][] exposes the details of Sass's inner workings.
 
-[plain CSS function]: functions/css
 [`sass:math` module]: modules/math
 [numbers]: values/numbers
 [`sass:string` module]: modules/string
@@ -125,7 +124,7 @@ Sass provides the following built-in modules:
   unitless number between 0 and 1 (inclusive), or a percentage between `0%` and
   `100%` (inclusive).
 
-  [unitless]: ../values/numbers#units
+  [unitless]: values/numbers#units
 
   <% fun_fact do %>
     You can pass [special functions][] like `calc()` or `var()` in place of any
@@ -134,7 +133,7 @@ Sass provides the following built-in modules:
     function is called this way, it returns an unquoted string using the same
     signature it was called with.
 
-    [special functions]: ../syntax/special-functions
+    [special functions]: syntax/special-functions
 
     <% example(autogen_css: false) do %>
       @debug hsl(210deg 100% 20% / var(--opacity)); // hsl(210deg 100% 20% / var(--opacity))
@@ -151,7 +150,7 @@ Sass provides the following built-in modules:
     `hsl($hue $saturation $lightness / $alpha)` signature. Consider using
     `hsl($hue, $saturation, $lightness, $alpha)` instead.
 
-    [special parsing rules]: ../operators/numeric#slash-separated-values
+    [special parsing rules]: operators/numeric#slash-separated-values
   <% end %>
 
   <% example(autogen_css: false) do %>
@@ -223,7 +222,7 @@ Sass provides the following built-in modules:
   alpha channel can be specified as either a unitless number between 0 and 1
   (inclusive), or a percentage between `0%` and `100%` (inclusive).
 
-  [unitless]: ../values/numbers#units
+  [unitless]: values/numbers#units
 
   <% fun_fact do %>
     You can pass [special functions][] like `calc()` or `var()` in place of any
@@ -232,7 +231,7 @@ Sass provides the following built-in modules:
     function is called this way, it returns an unquoted string using the same
     signature it was called with.
 
-    [special functions]: ../syntax/special-functions
+    [special functions]: syntax/special-functions
 
     <% example(autogen_css: false) do %>
       @debug rgb(0 51 102 / var(--opacity)); // rgb(0 51 102 / var(--opacity))
@@ -249,7 +248,7 @@ Sass provides the following built-in modules:
     `rgb($red $green $blue / $alpha)` signature. Consider using
     `hsl($red, $green, $blue, $alpha)` instead.
 
-    [special parsing rules]: ../operators/numeric#slash-separated-values
+    [special parsing rules]: operators/numeric#slash-separated-values
   <% end %>
 
   <% example(autogen_css: false) do %>

source/documentation/modules/meta.html.md.erb

@@ -128,7 +128,7 @@ title: sass:meta
   [plain CSS function][].
 
   [user-defined]: ../at-rules/function
-  [plain CSS function]: css
+  [plain CSS function]: ../at-rules/function#plain-css-functions
 
   The returned function can be called using [`meta.call()`](#call).
 

source/documentation/operators.html.md.erb

@@ -22,7 +22,7 @@ introduction: >
   They're still supported in LibSass and Ruby Sass, but they'll produce warnings
   and users are strongly encouraged to avoid them.
 
-  [Color functions]: functions/color
+  [Color functions]: modules/color
 <% end %>
 
 ## Order of Operations

source/documentation/style-rules.html.md.erb

@@ -163,4 +163,4 @@ generating selectors. For more information, see the [parent selector
 documentation][].
 
 [`@at-root` rule]: at-rules/at-root
-[selector functions]: functions/selector
+[selector functions]: modules/selector

source/documentation/syntax/special-functions.html.md.erb

@@ -4,10 +4,10 @@ table_of_contents: true
 introduction: >
   CSS defines many functions, and most of them work just fine with Sass’s normal
   function syntax. They’re parsed as function calls, resolved to [plain CSS
-  functions](../modules/css), and compiled as-is to CSS. There are a few
-  exceptions, though, which have special syntax that can’t just be parsed as a
-  [SassScript expression](structure#expressions). All special function calls
-  return [unquoted strings](../values/strings#unquoted).
+  functions](../at-rules/function#plain-css-functions), and compiled as-is to
+  CSS. There are a few exceptions, though, which have special syntax that can’t
+  just be parsed as a [SassScript expression](structure#expressions). All
+  special function calls return [unquoted strings](../values/strings#unquoted).
 ---
 
 ## `url()`
@@ -27,7 +27,7 @@ calls][]—it's parsed as a normal [plain CSS function call][].
 [interpolation]: ../interpolation
 [variables]: ../variables
 [function calls]: ../at-rules/function
-[plain CSS function call]: ../modules/css
+[plain CSS function call]: ../at-rules/function#plain-css-functions
 
 <% example do %>
   $roboto-font-path: "../fonts/roboto";

source/documentation/values.html.md

@@ -33,5 +33,5 @@ A few more are specific to Sass:
 * [Function references](values/functions) returned by [`get-function()`][] and
   called with [`call()`][].
 
-[`get-function()`]: functions/meta#get-function
-[`call()`]: functions/meta#call
+[`get-function()`]: modules/meta#get-function
+[`call()`]: modules/meta#call

source/documentation/variables.html.md.erb

@@ -274,8 +274,8 @@ with the given name exists in the current scope, and the
 [`meta.global-variable-exists()` function][] does the same but only for the
 global scope.
 
-[`meta.variable-exists()` function]: functions/meta#variable-exists
-[`meta.global-variable-exists()` function]: functions/meta#global-variable-exists
+[`meta.variable-exists()` function]: modules/meta#variable-exists
+[`meta.global-variable-exists()` function]: modules/meta#global-variable-exists
 
 <% heads_up do %>
   Users occasionally want to use interpolation to define a variable name based