[css-text] Give word-break values a high-level desription.

--HG--
extra : rebase_source : d107482c1b0e4beda3e433be151104f065d72c0b

Author: fantasai

css-text/Overview.bs

@@ -932,18 +932,19 @@ Line Breaking Details</h3>
        allows breaks between any two consecutive Hangul/Hanja.
 
       <dt><dfn>break-all</dfn></dt>
-      <dd>In addition to ''word-break/normal'' <i>soft wrap opportunities</i>,
+      <dd>Breaking is allowed within “words”:
+        in addition to ''word-break/normal'' <i>soft wrap opportunities</i>,
         lines may break between any two <i>semantically-perceived letters</i>
         (except where forbidden by the 'line-break' property).
         Hyphenation is not applied. This option is used mostly in a context where
         the text is predominantly using CJK characters with few non-CJK excerpts
         and it is desired that the text be better distributed on each line.</dd>
 
       <dt><dfn>keep-all</dfn></dt>
-      <dd>
-        Implicit <i>soft wrap opportunities</i> between <i>semantically-perceived letters</i> are suppressed,
+      <dd>Breaking is forbidden within “words”:
+        implicit <i>soft wrap opportunities</i> between <i>semantically-perceived letters</i> are suppressed,
         i.e. breaks are prohibited between pairs of letters
-        (including those explicitly allowed by 'line-break')
+        (regardless of 'line-break' settings)
         except where opportunities exist due to dictionary-based breaking.
         Otherwise this option is equivalent to ''word-break/normal''.
         In this style, sequences of CJK characters do not break.

css-text/Overview.html

@@ -1103,18 +1103,19 @@ <h3 class="heading settled heading" data-level=5.2 id=word-break-property><span
        allows breaks between any two consecutive Hangul/Hanja.
 
       <dt><dfn class=css-code data-dfn-for=word-break data-dfn-type=value data-export="" id=valuedef-break-all>break-all<a class=self-link href=#valuedef-break-all></a></dfn></dt>
-      <dd>In addition to <a class=css data-link-for=word-break data-link-type=maybe href=#valuedef-normal1 title=normal>normal</a> <a data-link-type=dfn href=#soft-wrap-opportunity title="soft wrap opportunities">soft wrap opportunities</a>,
+      <dd>Breaking is allowed within “words”:
+        in addition to <a class=css data-link-for=word-break data-link-type=maybe href=#valuedef-normal1 title=normal>normal</a> <a data-link-type=dfn href=#soft-wrap-opportunity title="soft wrap opportunities">soft wrap opportunities</a>,
         lines may break between any two <a data-link-type=dfn href=#semantically-perceived-letter title="semantically-perceived letters">semantically-perceived letters</a>
         (except where forbidden by the <a class=property data-link-type=propdesc href=#propdef-line-break title=line-break>line-break</a> property).
         Hyphenation is not applied. This option is used mostly in a context where
         the text is predominantly using CJK characters with few non-CJK excerpts
         and it is desired that the text be better distributed on each line.</dd>
 
       <dt><dfn class=css-code data-dfn-for=word-break data-dfn-type=value data-export="" id=valuedef-keep-all>keep-all<a class=self-link href=#valuedef-keep-all></a></dfn></dt>
-      <dd>
-        Implicit <a data-link-type=dfn href=#soft-wrap-opportunity title="soft wrap opportunities">soft wrap opportunities</a> between <a data-link-type=dfn href=#semantically-perceived-letter title="semantically-perceived letters">semantically-perceived letters</a> are suppressed,
+      <dd>Breaking is forbidden within “words”:
+        implicit <a data-link-type=dfn href=#soft-wrap-opportunity title="soft wrap opportunities">soft wrap opportunities</a> between <a data-link-type=dfn href=#semantically-perceived-letter title="semantically-perceived letters">semantically-perceived letters</a> are suppressed,
         i.e. breaks are prohibited between pairs of letters
-        (including those explicitly allowed by <a class=property data-link-type=propdesc href=#propdef-line-break title=line-break>line-break</a>)
+        (regardless of <a class=property data-link-type=propdesc href=#propdef-line-break title=line-break>line-break</a> settings)
         except where opportunities exist due to dictionary-based breaking.
         Otherwise this option is equivalent to <a class=css data-link-for=word-break data-link-type=maybe href=#valuedef-normal1 title=normal>normal</a>.
         In this style, sequences of CJK characters do not break.