[css-text] Fix 'text-indent' grammar to follow the Lea Verou principle (fully reorderable unless ambiguous)

Author: fantasai

css-text/Overview.html

@@ -2815,7 +2815,7 @@ <h2 id=edge-effects><span class=secno>9. </span> Edge Effects</h2>
 
   <p>Edge effects control the indentation of lines with respect to other
    lines in the block (‘<a href="#text-indent0"><code
-   class=property>text-indent</code></a>’) and how content is aligned to
+   class=property>text-indent</code></a>’) and how content is measured at
    the start and end edges of a line (‘<a
    href="#hanging-punctuation0"><code
    class=property>hanging-punctuation</code></a>’).
@@ -2838,7 +2838,7 @@ <h3 id=text-indent><span class=secno>9.1. </span> First Line Indentation:
       href="http://www.w3.org/TR/CSS21/syndata.html#value-def-length">&lt;length&gt;</a></span>
       | <span class=value-inst-percentage><a
       href="http://www.w3.org/TR/CSS21/syndata.html#value-def-percentage">&lt;percentage&gt;</a></span>
-      ] && [ hanging || each-line ]?
+      ] && hanging? && each-line?
 
     <tr>
      <th>Initial:
@@ -3910,7 +3910,7 @@ <h2 class=no-num id=appendix-g-full-property-index>Appendix G: Full
     <tr>
      <th><a class=property href="#text-indent0">text-indent</a>
 
-     <td>[ &lt;length&gt; | &lt;percentage&gt; ] && [ hanging || each-line ]?
+     <td>[ &lt;length&gt; | &lt;percentage&gt; ] && hanging? && each-line?
 
      <td>0
 

css-text/Overview.src.html

@@ -2178,7 +2178,7 @@ <h3 id="text-indent">
           <th><a href="#values">Value</a>:
           <td>[ <span class="value-inst-length"><a href="http://www.w3.org/TR/CSS21/syndata.html#value-def-length">&lt;length&gt;</a></span>
               | <span class="value-inst-percentage"><a href="http://www.w3.org/TR/CSS21/syndata.html#value-def-percentage">&lt;percentage&gt;</a></span>
-              ] && [ hanging || each-line ]?
+              ] && hanging? && each-line?
           </td>
         </tr>
         <tr>