Use zero width for copy height (php-debugbar#677)

Author: barryvdh

src/DebugBar/Resources/widgets/sqlqueries/widget.css

@@ -57,7 +57,6 @@ div.phpdebugbar-widgets-sqlqueries span.phpdebugbar-widgets-stmt-id:before {
 }
 div.phpdebugbar-widgets-sqlqueries span.phpdebugbar-widgets-copy-clipboard:before {
   content: "\f0c5";
-  line-height: 1.5;
 }
 div.phpdebugbar-widgets-sqlqueries span.phpdebugbar-widgets-copy-clipboard-check:before {
   content: "\f46c";

src/DebugBar/Resources/widgets/sqlqueries/widget.js

@@ -123,6 +123,7 @@
                     $('<span title="Copy to clipboard" />')
                         .addClass(csscls('copy-clipboard'))
                         .css('cursor', 'pointer')
+                        .html("&#8203;")
                         .on('click', function (event) {
                             self.onCopyToClipboard(this);
                             event.stopPropagation();