[css-text-3] Merge two sections so that all of line breaking is one chapter. w3c#2559

Author: fantasai

css-text-3/Overview.bs

@@ -1173,7 +1173,7 @@ Line Breaking Details</h3>
       (see [[#word-break-shaping]]).
 
   <h3 id="line-break-property">
-    Line Breaking Rules: the 'line-break' property</h3>
+    Line Breaking Strictness: the 'line-break' property</h3>
 
     <pre class="propdef">
     Name: line-break
@@ -1308,7 +1308,8 @@ Line Breaking Details</h3>
       specification finer control over line breaking may be necessary to
       satisfy high-end publishing requirements.
 
-<h2 id="hyphenation">Breaking Within Words</h2>
+  <h3 id="hyphenation" oldids="hyphens-property" caniuse="css-hyphens">
+    Hyphenation: the 'hyphens' property</h3>
 
     <p><dfn id=hyphenate lt="hyphenation|hyphenate">Hyphenation</dfn>
       allows the controlled splitting of words
@@ -1332,13 +1333,6 @@ Line Breaking Details</h3>
          which is particularly important in long-word languages like German.
          https://bugzilla.mozilla.org/show_bug.cgi?id=418975 -->
 
-    <p>CSS also provides the 'overflow-wrap' property, which can allow
-      arbitrary breaking within words when the text would otherwise overflow
-      its container.
-
-  <h3 id="hyphens-property" caniuse="css-hyphens">
-    Hyphenation Control: the 'hyphens' property</h3>
-
     <pre class="propdef">
     Name: hyphens
     Value: none | manual | auto