Remove contradictory normative "must" from Section 7 preamble (first step to address transaction-amount issue in 1.3.5) (#4458)

* this is not a success criterion - it should not contain normative
*must* statements that create specific "new" requirements by the
backdoor
* the *must* here is contradicted in the sentence immediately following,
where it starts with "Where applicable"?

This is related to
#4362 (comment)

For info, this may also be relevant
#3777

Co-authored-by: Mike Gower <mikegower@gmail.com>
(cherry picked from commit 9e20466)

Author: 2 people

guidelines/input-purposes.html

@@ -1,6 +1,6 @@
 <section id="input-purposes">
 	<h2>Input Purposes for User Interface Components</h2>
-	<p>This section contains a listing of common <a>user interface component</a> input purposes. The terms below are not keywords that must be used, but instead represent purposes that must be captured in the taxonomy adopted by a webpage. Where applicable, authors mark up controls with the chosen taxonomy to indicate the semantic purpose. This provides the potential for user agents and assistive technologies to apply personalized presentations that can enable more people to understand and use the content.</p>
+	<p>This section contains a listing of common <a>user interface component</a> input purposes. The terms below are not keywords that must be used, but instead represent purposes that can be captured in the taxonomy adopted by a webpage. Where applicable, authors mark up controls with the chosen taxonomy to indicate the semantic purpose. This provides the potential for user agents and assistive technologies to apply personalized presentations that can enable more people to understand and use the content.</p>
 
   <p class="note">The list of input type purposes is based on the control purposes defined in the <a href="https://www.w3.org/TR/html52/sec-forms.html#sec-autofill">HTML 5.2 Autofill field section</a>, but it is important to understand that a different technology may have some or all of the same concepts defined in its specification and only the concepts that are mapped to the meanings below are required.</p>
 
@@ -61,5 +61,5 @@ <h2>Input Purposes for User Interface Components</h2>
 		<li><strong>email</strong> - E-mail address</li>
 		<li><strong>impp</strong> - URL representing an instant messaging protocol endpoint (for example, "<strong>aim:goim?screenname=example</strong>" or "<strong>xmpp:fred@example.net</strong>")</li>
 	</ul>
-	
+
 </section>