[css-logical] Define the border-<block>-<inline>-radius logical properties (#1776)

Author: FremyCompany

css-logical-1/Overview.bs

@@ -548,6 +548,19 @@ the 'border-block-start', 'border-block-end', 'border-inline-start', 'border-inl
   'border-inline-start' & 'border-inline-end',
   respectively.
 
+<h3 id="border-radius-shorthands">
+Flow-relative Border-radius Shorthands:
+the 'border-start-start-radius', 'border-start-end-radius', 'border-end-start-radius', 'border-end-end-radius' properties</h3>
+
+  <pre class="propdef shorthand">
+  Name: border-start-start-radius, border-start-end-radius, border-end-start-radius, border-end-end-radius
+  Value: <<'border-top-left-radius'>>
+  </pre>
+
+  These properties correspond to the
+  'border-top-left', 'border-bottom-left', 'border-top-right', and 'border-bottom-right' properties.
+  The mapping depends on the element's 'writing-mode', 'direction', and 'text-orientation'.
+
 <h3 id="logical-shorthand-keyword">
 Four-Directional Shorthand Properties: the 'margin', 'padding', 'border-width', 'border-style', and 'border-color' shorthands</h3>