[K/N] Make target deprecation warning more visible

Two columns in Gradle output makes IDE display such
message in a separate view which makes it more discoverable.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanDriver.kt

@@ -64,7 +64,7 @@ class KonanDriver(
         // Avoid showing warning twice in 2-phase compilation.
         if (konanConfig.produce != CompilerOutputKind.LIBRARY && konanConfig.target in deprecatedTargets) {
             configuration.report(CompilerMessageSeverity.STRONG_WARNING,
-                    "target ${konanConfig.target} is deprecated and will be removed soon. See $DEPRECATION_LINK")
+                    "target ${konanConfig.target} is deprecated and will be removed soon. See: $DEPRECATION_LINK")
         }
 
         ensureModuleName(konanConfig)