[css-grid] Update DoC

Author: fantasai

css-grid/issues-wd-20160519.bsi

@@ -146,3 +146,9 @@ Comment:   https://github.com/w3c/csswg-drafts/issues/353
 Closed:    Rejected
 Resolved:  Editor's discretion
 ----
+Issue 20.
+Summary:   Drop <percentage> tracks
+From:      Sergio Villar Senin
+Comment:   https://github.com/w3c/csswg-drafts/issues/345
+Open:      =WG= Discuss.
+----

css-grid/issues-wd-20160519.html

@@ -178,6 +178,12 @@ <h1>CSS Grid Layout Level 1 Disposition of Comments for 2016-05-19 WD</h1>
 <span>Comment:   <a href='https://github.com/w3c/csswg-drafts/issues/353'>https://github.com/w3c/csswg-drafts/issues/353</a></span>
 <span class="r">Closed:    Rejected</span>
 <span>Resolved:  Editor's discretion</span></pre>
+<pre class='open ' id='issue-20'>
+<span>Issue 20. <a href='#issue-20'>#</a></span>
+<span>Summary:   Drop &lt;percentage> tracks</span>
+<span>From:      Sergio Villar Senin</span>
+<span>Comment:   <a href='https://github.com/w3c/csswg-drafts/issues/345'>https://github.com/w3c/csswg-drafts/issues/345</a></span>
+<span class="">Open:      =WG= Discuss.</span></pre>
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