🐛 Fix alert overflow when it contains a code block

The alert text span is a flex item with the default min-width: auto,
so it cannot shrink below its widest child. A code block or table in
an alert ran past the alert box, and on phones made the page wider
than the screen.

Add min-w-0 to the text span in both the default and textColor
branches so wide content scrolls inside the alert.

layouts/shortcodes/alert.html

@@ -27,9 +27,9 @@
 
   <span
     {{ if not ($.Scratch.Get "textColor") }}
-      class="dark:text-neutral-300"
+      class="min-w-0 dark:text-neutral-300"
     {{ else }}
-      style="color: {{ $.Scratch.Get "textColor" }}"
+      class="min-w-0" style="color: {{ $.Scratch.Get "textColor" }}"
     {{ end }}
     >
     {{- .Inner | markdownify -}}