Spin Button and Combobox Patterns: Sync Guidance About Platform Speci…

…fic Editing Keys

For issue #413, modified the Combobox and Spin Button design patterns in aria-practices.html:

1. In key assignment lists  of both patterns, use the same wording to make it more clear that the pattern requires platform appropriate editing key assignments.
2. Revise the notes in  both patterns to use list format and more succinctly  describe guidance.

aria-practices.html

@@ -665,6 +665,7 @@ <h5>Textbox Keyboard Interaction</h5>
             For example, in a messaging application, the default action may be to add the accepted value to a list of message recipients and then clear the textbox so the user can add another recipient.
           </li>
           <li>Printable Characters: Type characters in the textbox. Note that some implementations may regard certain characters as invalid and prevent their input.</li>
+          <li>Standard single line text editing keys appropriate for the device platform (see note below).</li>
           <li><kbd>Alt + Down Arrow</kbd> (Optional): If the popup is available but not displayed, displays the popup without moving focus.</li> 
           <li><kbd>Alt + Up Arrow</kbd> (Optional): If the popup is displayed:
             <ol>
@@ -673,12 +674,13 @@ <h5>Textbox Keyboard Interaction</h5>
             </ol>
           </li>
         </ul>
-        <p class="note">
-          The textbox supports standard keyboard commands for text editing functions, including input, navigation, selection, and manipulation.
-          Standard key assignments for these functions depend on the device operating system.
-          The most robust approach to providing text editing functions is to rely on browsers, which  supply them for HTML inputs with type text and for elements with the contenteditable attribute.
-          <strong>IMPORTANT:</strong> Be sure that JavaScript does not interfere with browser-provided text editing functions by capturing key events for the keys used to perform them.
-        </p>
+        <p class="note">Standard single line text editing keys appropriate for the device platform:</p>
+        <ol>
+          <li>include keys for input, cursor movement, selection, and text manipulation.</li>
+          <li>Standard key assignments for editing functions depend on the device operating system.</li>
+          <li>The most robust approach for providing text editing functions is to rely on browsers, which  supply them for HTML inputs with type text and for elements with the <code>contenteditable</code> HTML attribute.</li>
+          <li><strong>IMPORTANT:</strong> Be sure that JavaScript does not interfere with browser-provided text editing functions by capturing key events for the keys used to perform them.</li>
+        </ol>
         <h5>Listbox Popup Keyboard Interaction</h5>
         <p>When focus is in a listbox popup:</p>
         <ul>
@@ -2253,24 +2255,34 @@ <h4>Example</h4>
       <section class="notoc">
         <h4>Keyboard Interaction</h4>
         <ul>
-          <li>Text editing keys: If the spinbutton text field allows directly editing the value, the following keys are supported.
+          <li><kbd>Up Arrow</kbd>: Increases the value.</li>
+          <li><kbd>Down Arrow</kbd>: Decreases the value.</li>
+          <li><kbd>Home</kbd>: If the spinbutton has a minimum value, sets the value to its minimum.</li>
+          <li><kbd>End</kbd>: If the spinbutton has a maximum value, sets the value to its maximum.</li>
+          <li><kbd>Page Up</kbd> (Optional): Increases the value by a larger step than <kbd>Up Arrow</kbd>.</li>
+          <li><kbd>Page Down</kbd> (Optional): Decreases the value by a larger step than <kbd>Down Arrow</kbd>.</li>
+          <li>If the spinbutton text field allows directly editing the value, the following keys are supported:
             <ul>
-              <li>Standard single line text field keys, such as <kbd>Left Arrow</kbd>, <kbd>Right Arrow</kbd>, <kbd>Shift + Left Arrow</kbd>, <kbd>Shift + Right Arrow</kbd>, and <kbd>Delete</kbd>, for cursor movement, selecting text, and text deletion.</li>
+              <li>Standard single line text editing keys appropriate for the device platform (see note below).</li>
               <li>
-                Characters that are permitted to be part of the value.
+                Printable Characters: Type characters in the textbox. Note that many implementations allow only certain characters as part of the value and prevent input of any other characters.
                 For example, an hour-and-minute spinner would allow only integer values from 0 to 59, the colon ':', and the letters 'AM' and 'PM'.
                 Any other character input does not change the contents of the text field nor the value of the spinbutton.
               </li>
             </ul>
           </li>
-          <li><kbd>Up Arrow</kbd>: Increases the value.</li>
-          <li><kbd>Down Arrow</kbd>: Decreases the value.</li>
-          <li><kbd>Home</kbd>: If the spinbutton has a minimum value, sets the value to its minimum.</li>
-          <li><kbd>End</kbd>: If the spinbutton has a maximum value, sets the value to its maximum.</li>
-          <li><kbd>Page Up</kbd> (Optional): Increases the value by a larger step than <kbd>Up Arrow</kbd>.</li>
-          <li><kbd>Page Down</kbd> (Optional): Decreases the value by a larger step than <kbd>Down Arrow</kbd>.</li>
         </ul>
-        <p class="note">Focus remains on the text field during operation.</p>
+        <ol class="note">
+          <li>Focus remains on the text field during operation.</li>
+          <li>Standard single line text editing keys appropriate for the device platform:
+            <ol>
+              <li>include keys for input, cursor movement, selection, and text manipulation.</li>
+              <li>Standard key assignments for editing functions depend on the device operating system.</li>
+              <li>The most robust approach for providing text editing functions is to rely on browsers, which  supply them for HTML inputs with type text and for elements with the <code>contenteditable</code> HTML attribute.</li>
+              <li><strong>IMPORTANT:</strong> Be sure that JavaScript does not interfere with browser-provided text editing functions by capturing key events for the keys used to perform them.</li>
+            </ol>
+          </li>
+        </ol>
       </section>
 
       <section class="notoc">