Issue #121 - Use legacy name alias concept as defined by CSS (#155)

https://drafts.csswg.org/css-cascade-5/#aliasing

compatibility.bs

@@ -7,6 +7,7 @@ Text Macro: LATESTRD 2021-06
 Abstract: This standard describes a collection of non-standard (and often vendor-prefixed) CSS properties and DOM APIs that web browsers need to support for compatibility with the de facto web.
 Translation: ja https://triple-underscore.github.io/compat-ja.html
 Indent: 2
+Markup Shorthands: dfn yes
 </pre>
 
 <pre class="anchors">
@@ -202,9 +203,9 @@ Both the [[css3-images-20110217]] draft <code>-webkit-</code> prefixed <<image>>
 
 <h3 id="css-properties">CSS Properties</h3>
 
-<h4 id="css-simple-aliases">Simple property aliases</h4>
+<h4 id="css-simple-aliases">Legacy name aliases</h4>
 
-The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be supported as aliases of the corresponding unprefixed property:
+The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be supported as <a lt="legacy name alias">legacy name aliases</a> of the corresponding unprefixed property:
 
 <table>
   <thead>
@@ -274,7 +275,7 @@ The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be su
       <td>
         <code><dfn property>-webkit-background-size</dfn></code>
         <p class="XXX">
-          Not simple. See <a href="https://github.com/whatwg/compat/issues/28">issue #28</a>.
+          Not really a [=legacy name alias=]. See <a href="https://github.com/whatwg/compat/issues/28">issue #28</a>.
         </p>
       </td>
       <td><code>'background-size'</code></td>
@@ -446,9 +447,9 @@ The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be su
   </tbody>
 </table>
 
-<h4 id="css-prefixed-aliases">Prefixed property aliases</h4>
+<h4 id="css-prefixed-aliases">Prefixed legacy name aliases</h4>
 
-The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be supported as aliases of the corresponding unprefixed properties. If the user agent does not ship the unprefixed equivalent, the <code>-webkit-</code> prefixed property must be treated as an alias of the user agent's own vendor prefixed property.
+The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be supported as <a lt="legacy name alias">legacy name aliases</a> of the corresponding unprefixed properties. If the user agent does not ship the unprefixed equivalent, the <code>-webkit-</code> prefixed property must be treated as an alias of the user agent's own vendor prefixed property.
 
 <table>
   <thead>
@@ -466,7 +467,7 @@ The following <code>-webkit-</code> <a>vendor prefixed</a> properties must be su
 </table>
 
 <br>
-<div class="note">As soon as each property is unprefixable it can be defined as a "simple" alias.</div>
+<div class="note">As soon as each property is unprefixable it can be defined as a [=legacy name alias=].</div>
 
 <h4 id="css-non-aliased">Non-aliased vendor prefixed properties</h4>
 
@@ -556,7 +557,7 @@ Animation type: discrete
 
 The <code>'-webkit-background-clip'</code> property&mdash;when its value is ''text''&mdash;creates a background <a>clipping region</a> from the outer text stroke of the foreground text (including alpha transparency).
 
-The <code>'-webkit-background-clip'</code> property is a simple alias of the 'background-clip' property for all other <<box>> values.
+The <code>'-webkit-background-clip'</code> property is a [=legacy name alias=] of the 'background-clip' property for all other <<box>> values.
 
 <div class="note">
 Note that the root element has a different background painting area, and thus the '-webkit-background-clip' property has no effect when specified on it. See <a>the backgrounds of special elements</a>.