XEP-0393: remove disabling individual spans/blocks

This was a nice workaround, but a convenient code point that is actually
for this sort of use can't be found.

xep-0393.xml

@@ -26,6 +26,18 @@
   <supersededby/>
   <shortname>styling</shortname>
   &sam;
+  <revision>
+    <version>0.4.0</version>
+    <date>2020-06-02</date>
+    <initials>ssw</initials>
+    <remark>
+      <p>
+        Remove description of mechanism for disabling styling on individual
+        spans and blocks, users can do this themselves without us documenting
+        the use of a codepoint that's not specifically for this purpose.
+      </p>
+    </remark>
+  </revision>
   <revision>
     <version>0.3.0</version>
     <date>2020-06-02</date>
@@ -471,24 +483,8 @@
     On rare occasions styling hints may conflict with the contents of a message.
     For example, if the user sends the emoji "&gt; _ &lt;" it would be
     interpreted as a block quote.
-  </p>
+    Senders may indicate to the receiver that a particular message SHOULD NOT be
-
+    styled by adding an empty &lt;unstyled&gt; element qualified by the
-  <section2 topic='Individual Directives'>
-    <p>
-      To remove styling without removing the styling directives, a whitespace
-      character can be inserted after the opening styling directive and before
-      the closing styling directive (if applicable).
-      This whitespace character SHOULD be U+2060 WORD JOINER to prevent line
-      breaks between the character that was misinterpreted as a styling
-      directive and the text that it would otherwise style.
-    </p>
-  </section2>
-  <section2 topic='Entire Messages'>
-    <p>
-      An entire message may also have styling disabled to remove the need to
-      parse the message for styling in the first place.
-      Senders may indicate to the receiver that a particular message SHOULD NOT
-      be styled by adding an empty &lt;unstyled&gt; element qualified by the
     "urn:xmpp:styling:0" namespace.
   </p>
   <example caption='Sender indicates that styling is disabled'><![CDATA[
@@ -497,7 +493,6 @@
   <unstyled xmlns="urn:xmpp:styling:0"/>
 </message>
 ]]></example>
-  </section2>
 </section1>
 <section1 topic='Implementation Notes' anchor='impl'>
   <p>
@@ -514,6 +509,13 @@
     For example, the string "*emphasis*" would be rendered as
     "<strong>*emphasis*</strong>".
   </p>
+  <p>
+    This specification does not provide a mechanism for removing styling from
+    individual spans or blocks within a styled message.
+    Implementations are free to implement their own workarounds, for example by
+    inserting Unicode non-printable characters to invalidate styling directives,
+    but no specific technique is known to be widely supported.
+  </p>
 </section1>
 <section1 topic='Accessibility Considerations' anchor='access'>
   <p>