lib: remove unused function argument (nodejs#96)

The `{colors: true}` removed here is ignored by the function it is being
sent to.

lib/internal/inspector/inspect_repl.js

@@ -581,7 +581,7 @@ function createRepl(inspector) {
         const lines = watchedExpressions
           .map((expr, idx) => {
             const prefix = `${leftPad(idx, ' ', lastIndex)}: ${expr} =`;
-            const value = inspect(values[idx], { colors: true });
+            const value = inspect(values[idx]);
             if (value.indexOf('\n') === -1) {
               return `${prefix} ${value}`;
             }