[css-text-3] Clean up changes log from 2013-2018 by referencing more exhaustive resources like the DoC, diffs, and commit logs.

Author: fantasai

css-text-3/Overview.bs

@@ -6715,11 +6715,18 @@ Changes</h2>
   Changes from the <a href="https://www.w3.org/TR/2013/WD-css-text-3-20131010/">October
   2013 CSS3 Text <abbr title="Last Call Working Draft">LCWD</abbr></a></h3>
 
-  ISSUE: THIS CHANGES LIST IS WAY INCOMPLETE PLEASE SEE
-  <a href="https://drafts.csswg.org/css-text-3/issues-lc-2013">Disposition of Comments</a>.
+  Numerous significant changes were made
+  between the <a href="https://www.w3.org/TR/2013/WD-css-text-3-20131010/">10 October 2013 Last Call Working Draft</a>
+  and the <a href="https://www.w3.org/TR/2018/WD-css-text-3-20181206/">6 December 2018 Working Draft</a>
+  in response to <a href="https://drafts.csswg.org/css-text-3/issues-lc-2013">comments</a>,
+  oftentimes overwriting or reverting earlier changes.
+  While the general scope and approach of this specification is unchanged,
+  myriad details did change.
+
+  A handful of the more significant changes are highlighted below:
 
   <ul>
-    <li>Switched 'tab-size' to use <<number>> so that it is animatable,
+    <li>Switched 'tab-size' to use <<number>> instead of <<integer> so that it is animatable,
         and defined it to also account for 'letter-spacing' and 'word-spacing'.
     <li>Made 'text-align' a shorthand of 'text-align-last' and the new 'text-align-all' property.
     <li>Removed dependence of 'text-align-last' on ''text-align: justify'',
@@ -6728,9 +6735,19 @@ Changes</h2>
     <li>For ''word-break: break-all'', included non-letters that are treated as letter-like in [[UAX14]]
         to handle symbols better.
     <li>Added ''line-break: anywhere'' and ''overflow-wrap: anywhere''.
-    <li>Tweaked handling of Ambiguous characters during <a href="#line-break-transform">segment break transformation</a> to respond to language context.
+    <li>Tweaked handling of Ambiguous characters during <a href="#line-break-transform">segment break transformation</a>.
   </ul>
 
+  <strong>Most of the changes since 2013 are details not tracked in this list.</strong>
+  If you have last reviewed this specification
+  before publication of the <a href="https://www.w3.org/TR/2018/WD-css-text-3-20181206/">6 December 2018 Working Draft</a>,
+  it's probably advisable to simply read it from scratch.
+  For an exhaustive list of changes since 2013,
+  please see the <code>css-text-3</code> and <code>css3-text</code> <a href="https://github.com/w3c/csswg-drafts">commit logs</a>
+  or the <a href="https://services.w3.org/htmldiff?doc1=&doc2=https%3A%2F%2Fwww.w3.org%2FTR%2F2018%2FWD-css-text-3-20181206%2F">diff between 2013 and 2018</a>.
+  For an exhaustive list of issues addressed,
+  see the <a href="https://drafts.csswg.org/css-text-3/issues-lc-2013">Disposition of Comments</a>.
+
     <!-- Listing crash tests not particularly linked to any specific spot in the spec-->
     <wpt>
     removing-collapsible-crash.html