[css-backgrounds-3] Update link to 2012 DoC

Author: fantasai

css-backgrounds-3/Overview.html

@@ -2856,7 +2856,7 @@ <h3 class="heading settled" data-level="9.5" id="changes-2012LC"><span class="se
    <p>The following (non-editorial) changes were made to this
 specification since the <a href="https://www.w3.org/TR/2012/WD-css3-background-20120214/">14 February 2012 “Last Call” Working Draft</a>: </p>
    <p>These changes were in response to comments received during the
-review period. For details, see the full <a href="issues-lc-2012.html">Disposition of Comments.</a> </p>
+review period. For details, see the full <a href="https://drafts.csswg.org/css-backgrounds-3/issues-lc-2012">Disposition of Comments.</a> </p>
    <ul>
     <li><a href="#placement">Section 2.1</a>: Defined which properties
   from this module apply to the <a class="css" data-link-type="maybe" href="https://drafts.csswg.org/selectors-3/#sel-first-line" id="ref-for-sel-first-line②">::first-line</a> and <a class="css" data-link-type="maybe" href="https://drafts.csswg.org/selectors-3/#first-letter0" id="ref-for-first-letter0">::first-letter</a> pseudo-elements. 

css-backgrounds-3/Overview.src.html

@@ -3134,7 +3134,7 @@ <h3 id="changes-2012LC">
 >14 February 2012 “Last Call” Working Draft</a>:
 
 <p>These changes were in response to comments received during the
-review period. For details, see the full <a href="issues-lc-2012.html"
+review period. For details, see the full <a href="https://drafts.csswg.org/css-backgrounds-3/issues-lc-2012"
 >Disposition of Comments.</a>
 
 <ul>