[css-flexbox-1] Update DoC

Author: fantasai

css-flexbox-1/issues-cr-2018.bsi

@@ -458,3 +458,15 @@ Resolved: https://lists.w3.org/Archives/Public/www-style/2022Mar/0001.html
 Resolved: https://lists.w3.org/Archives/Public/www-style/2022May/0002.html
 ----
 Issue 53.
+Summary:  Inconsistent units for flex fractions is confusing
+From:     David Grogan
+Comment:  https://github.com/w3c/csswg-drafts/issues/6909
+Response: https://github.com/w3c/csswg-drafts/issues/6909#issuecomment-1009378118
+Closed:   Retracted
+Verified: https://github.com/w3c/csswg-drafts/issues/6909#issuecomment-1015027475
+Comment:  https://github.com/w3c/csswg-drafts/issues/6909#issuecomment-1015674529
+Response: https://github.com/w3c/csswg-drafts/issues/6909#issuecomment-1079498318
+Changes:  https://github.com/w3c/csswg-drafts/commit/034e66671f05c4ba0c45cc20c79611c4747f18dc
+Closed:   Accepted
+Resolved: Editorial
+----