Add Wall of Browser Bugs entry for #21092

Refs https://bugzilla.mozilla.org/show_bug.cgi?id=1315994
Refs #21092
[ci skip]

docs/_data/browser-bugs.yml

@@ -168,6 +168,16 @@
   origin: >
     Bootstrap#12359
 
+-
+  browser: >
+    Firefox
+  summary: >
+    Layout with floated columns breaks when printing
+  upstream_bug: >
+    Mozilla#1315994
+  origin: >
+    Bootstrap#21092
+
 -
   browser: >
     Firefox (Windows)