Add Wall of Browser Bugs entry for Safari related to #17438 / #14237

https://bugs.webkit.org/show_bug.cgi?id=149935
[skip sauce]

docs/_data/browser-bugs.yml

@@ -178,6 +178,16 @@
   origin: >
     Bootstrap#16814
 
+-
+  browser: >
+    Safari
+  summary: >
+    Unexplained `1px` horizontal space between `display: table-cell` elements
+  upstream_bug: >
+    WebKit#149935
+  origin: >
+    Bootstrap#17438, Bootstrap#14237
+
 -
   browser: >
     Safari (OS X)