doc: rename references to xsl instead of xls (#421)

XSL is the stylesheet for XML, XLS is a spreadsheet file format for Microsoft Excel

docs/content/2.guides/6.customising-ui.md

@@ -3,12 +3,12 @@ title: Customising the UI
 description: Change the look and feel of your sitemap.
 ---
 
-## Disabling the XLS
+## Disabling the XSL
 
-What you're looking at when you view the sitemap.xml is a XLS file, think of it just like you would a CSS file for HTML.
+What you're looking at when you view the sitemap.xml is a XSL file, think of it just like you would a CSS file for HTML.
 
 To view the real sitemap.xml, you can view the source of the page.
-If you prefer, you can disable the XLS by setting `xsl` to `false`.
+If you prefer, you can disable the XSL by setting `xsl` to `false`.
 
 ```ts
 export default defineNuxtConfig({
@@ -38,7 +38,7 @@ export default defineNuxtConfig({
 })
 ```
 
-The `select` you provide is an XLS expression that will be evaluated against the sitemap entry.
+The `select` you provide is an XSL expression that will be evaluated against the sitemap entry.
 It's recommended to prefix the value with `sitemap:` if in doubt.
 
 ### Example: Adding priority and changefreq