feat(menu): Add ellipsis to cut long menu items (#13769)

## DESCRIBE YOUR PR

Instead of enlarging the text to two rows, long menu items get an
ellipsis at the end, like here:


![image](https://github.com/user-attachments/assets/2003c987-9127-4e8f-b6d2-90afe3aef103)


closes #13766
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## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [ ] Checked Vercel preview for correctness, including links
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Author: s1gr1d

src/components/sidebarTableOfContents/style.module.scss

@@ -18,6 +18,10 @@
     position: relative;
     line-height: 1.5;
     display: block;
+    text-overflow: ellipsis;
+    overflow: hidden;
+    white-space: nowrap;
+
     color: var(--link-color);
     padding: 0.25em 0;
     opacity: 0.8;