Amend the note for focus appearance (#3657)

Removes the reference to "encloses" (which still comes from an earlier
version of the SC text) and "size", and instead uses "perimeter" which
is directly relevant to the normative text itself

See #3510 (comment)


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title="Last updated on Feb 29, 2024, 8:46 PM UTC (2b8f1be)">Preview</a>
| <a
href="https://pr-preview.s3.amazonaws.com/w3c/wcag/3657/33a5559...2b8f1be.html"
title="Last updated on Feb 29, 2024, 8:46 PM UTC (2b8f1be)">Diff</a>

Co-authored-by: Bruce Bailey <bailey@access-board.gov>

guidelines/sc/22/focus-appearance.html

@@ -1,10 +1,9 @@
 <section id="focus-appearance" class="sc new">
-
     <h4>Focus Appearance</h4>
-    
+
     <p class="conformance-level">AAA</p>
 	<p class="change">New</p>
-    
+
     <p>When the keyboard <a>focus indicator</a> is visible, an area of the focus indicator meets all the following:</p>
     <ul>
         <li>is at least as large as the area of a 2 <a>CSS pixel</a> thick <a>perimeter</a> of the unfocused component or sub-component, and</li>
@@ -13,14 +12,14 @@ <h4>Focus Appearance</h4>
 
     <p>Exceptions:</p>
     <ul>
-      <li>The focus indicator is determined by the <a>user agent</a> and cannot be adjusted by the author, or</li>
+        <li>The focus indicator is determined by the <a>user agent</a> and cannot be adjusted by the author, or</li>
         <li>The focus indicator and the indicator's background color are not modified by the author.</li>
     </ul>
-    
-    <p class="note">What is perceived as the user interface component or sub-component (to determine enclosure or size) depends on its visual <a>presentation</a>. The visual presentation includes the component's visible <a>content</a>, border, and component-specific background. It does not include shadow and glow effects outside the component's content, background, or border.</p>
+
+    <p class="note">What is perceived as the user interface component or sub-component (to determine the perimeter) depends on its visual <a>presentation</a>. The visual presentation includes the component's visible <a>content</a>, border, and component-specific background. It does not include shadow and glow effects outside the component's content, background, or border.</p>
 
     <p class="note">Examples of sub-components that may receive a focus indicator are menu items in an opened drop-down menu, or focusable cells in a grid.</p>
 
     <p class="note">Contrast calculations can be based on colors defined within the <a>technology</a> (such as HTML, CSS and SVG). Pixels modified by user agent resolution enhancements and anti-aliasing can be ignored.</p>
 
- </section>
+</section>