fix(line-numbers): avoid self-closing tag to address Svelte 5 warning (#342)

Fixes #341

Author: metonym

src/LineNumbers.svelte

@@ -48,7 +48,7 @@
               <div
                 class:line-background={true}
                 style:background="var(--highlighted-background, {HIGHLIGHTED_BACKGROUND})"
-              />
+              ></div>
             {/if}
           </td>
           <td>
@@ -57,7 +57,7 @@
               <div
                 class:line-background={true}
                 style:background="var(--highlighted-background, {HIGHLIGHTED_BACKGROUND})"
-              />
+              ></div>
             {/if}
           </td>
         </tr>