Remove scrollbar-gutter: stable to fix the gap right of the navbar (#3037)

Closes #3009

.changeset/fix-navbar-scrollbar-gutter-gap.md

@@ -0,0 +1,6 @@
+---
+"@tabler/core": patch
+"@tabler/docs": patch
+---
+
+Fixed the empty gutter to the right of the navbar on non-scrolling pages by dropping `scrollbar-gutter: stable` from `html`.

core/scss/layout/_core.scss

@@ -2,14 +2,6 @@
 
 @use '../config' as *;
 
-html {
-  scrollbar-gutter: stable;
-
-  @supports not (scrollbar-gutter: stable) {
-    overflow-y: scroll;
-  }
-}
-
 // stylelint-disable property-no-vendor-prefix
 body {
   position: relative;

docs/content/ui/getting-started/upgrade.mdx

@@ -273,7 +273,7 @@ These changes are not breaking, but they change how a page looks. Check your scr
 - **Links**: in dark mode, links use a lighter tint of the primary color, so they meet the 4.5:1 contrast ratio on dark surfaces. Override `--tblr-link-color` to change it.
 - **Sizes**: `.form-control`, `.btn` and `.input-group` now agree on `sm` and `lg` sizes, `.btn-icon` is square, and `.icon-sm` uses a `1.5` stroke width.
 - **Cards**: `--tblr-card-header-bg` and `--tblr-card-footer-bg` can be set on their own, and the card status bar is `3px`.
-- **Layout**: `scrollbar-gutter: stable` on `html` removes the white gap next to the scrollbar.
+- **Layout**: the `margin-inline-start: calc(100vw - 100%)` hack on the root element is gone, so there is no white gap on the left when a scrollbar is present.
 - **Trending**: the component uses the `arrow-up` and `arrow-down` icons instead of `trending-up` and `trending-down`.
 
 ## RTL