v6: minor docs fixes (#42385)

* Adjust toast copy, placeholder, and font var

Update docs and styles: change toast example text to use "accent" wording, mark the default toast placement option as disabled to prevent it being selected as a valid value, and switch the table font variable from --bs-font-monospace to the standardized --bs-font-mono in _content.scss.

* fix typo

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: coliff

site/src/content/docs/components/toasts.mdx

@@ -193,7 +193,7 @@ Toasts can be themed with our [theme color utilities]([[docsref:/customize/theme
       <CloseButton dismiss="toast" />
     </div>
     <div class="toast-body">
-      This toast is a primary themed toast.
+      This toast is an accent-themed toast.
       <div class="hstack gap-2 mt-2">
         <button type="button" class="btn-solid btn-sm">Take action</button>
         <button type="button" class="btn-solid theme-secondary btn-sm" data-bs-dismiss="toast">Close</button>
@@ -235,7 +235,7 @@ Place toasts with custom CSS as you need them. The top right is often used for n
     <div class="mb-3">
       <label for="selectToastPlacement">Toast placement</label>
       <select class="form-control mt-2" id="selectToastPlacement">
-        <option value="" selected>Select a position...</option>
+        <option value="" selected disabled>Select a position...</option>
         <option value="top-0 start-0">Top left</option>
         <option value="top-0 start-50 translate-middle-x">Top center</option>
         <option value="top-0 end-0">Top right</option>

site/src/scss/_content.scss

@@ -45,7 +45,7 @@
       }
 
       td {
-        font-family: var(--bs-font-monospace);
+        font-family: var(--bs-font-mono);
 
         &:first-child {
           padding-inline-end: 1.5rem;