Merge branch '37058-readme-md-header-image-scale-not-limited' into 'master'

Resolve "README.md: Header image scale not limited"

Closes #37058, #37024, and #37230

See merge request !13869

app/assets/stylesheets/framework/typography.scss

@@ -25,6 +25,7 @@
     min-width: inherit;
     min-height: inherit;
     background-color: inherit;
+    max-width: 100%;
   }
 
   p a:not(.no-attachment-icon) img {