debug: fix repl icon in HC mode

src/vs/workbench/parts/debug/browser/media/debugViewlet.css

@@ -44,7 +44,7 @@
 }
 
 .monaco-workbench.hc-black .debug-action.toggle-repl {
-	content: url('repl-inverse.svg') center center no-repeat;;
+	background: url('repl-inverse.svg') center center no-repeat;
 }
 
 /* Debug viewlet trees */

src/vs/workbench/parts/debug/browser/media/repl-inverse.svg

-<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 32 32"><style type="text/css">.icon-canvas-transparent{opacity:0;fill:#F6F6F6;} .icon-vs-out{fill:#252526;} .icon-vs-bg{fill:#c5c5c5;} .icon-vs-fg{fill:#2a292c;}</style><path class="icon-canvas-transparent" d="M32 32h-32v-32h32v32z" id="canvas"/><path class="icon-vs-out" d="M32 28h-32v-24h32v24z" id="outline"/><path class="icon-vs-bg" d="M2 6v20h28v-20h-28zm26 18h-24v-16h24v16zm-13-8l-5.25 5.5-1.75-1.833 3.5-3.667-3.5-3.667 1.75-1.833 5.25 5.5z" id="iconBg"/><g id="iconFg"><path class="icon-vs-fg" d="M4 8v16h24v-16h-24zm5.75 13.5l-1.75-1.833 3.5-3.667-3.5-3.667 1.75-1.833 5.25 5.5-5.25 5.5z"/></g></svg>
+<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 32 32"><style type="text/css">.icon-canvas-transparent{opacity:0;fill:#F6F6F6;} .icon-vs-out{fill:#252526;} .icon-vs-bg{fill:#c5c5c5;} .icon-vs-fg{fill:#2a292c;}</style><path class="icon-canvas-transparent" d="M32 32h-32v-32h32v32z" id="canvas"/><path class="icon-vs-out" d="M32 28h-32v-24h32v24z" id="outline"/><path class="icon-vs-bg" d="M2 6v20h28v-20h-28zm26 18h-24v-16h24v16zm-13-8l-5.25 5.5-1.75-1.833 3.5-3.667-3.5-3.667 1.75-1.833 5.25 5.5z" id="iconBg"/><g id="iconFg"><path class="icon-vs-fg" d="M4 8v16h24v-16h-24zm5.75 13.5l-1.75-1.833 3.5-3.667-3.5-3.667 1.75-1.833 5.25 5.5-5.25 5.5z"/></g></svg>
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