Bug 1876220 - [devtools] Prevent selector highlighter to add new line…

… to clipboard when copy/pasting. r=devtools-reviewers,jdescottes.

Differential Revision: https://phabricator.services.mozilla.com/D199707

UltraBlame original commit: 3629891cc2d708bce0fda06ceb02f758865827c9

devtools/client/themes/rules.css

@@ -6033,6 +6033,26 @@ dimmed
 color
 )
 ;
+/
+*
+Prevent
+line
+break
+when
+copy
+/
+pasting
+an
+entire
+rule
+*
+/
+user
+-
+select
+:
+auto
+;
 }
 .
 ruleview