Update single-line logic of PrettyPrinter to improve 'toString' repre…

…sentation of protocol entities

Before the fix: LxMouseEvent (type = EnteredxAbs = 640yAbs = 512clickCount = 0causedByTouchEvent = falsebutton = 0popupTrigger = falsemodifiers = 0)
After the fix: LxMouseEvent ( type = Moved xAbs = 870 yAbs = 632 clickCount = 0 causedByTouchEvent = false button = 0 popupTrigger = false modifiers = 0 )

rd-kt/rd-core/src/main/kotlin/com/jetbrains/rd/util/string/PrettyPrinter.kt

@@ -8,7 +8,7 @@ enum class Eol(val value: String) {
     linux ("\n"),
     windows ("\r\n"),
     osSpecified (eol),
-    none("")
+    none(" ")
 }
 
 inline fun printer(content: PrettyPrinter.() -> Unit) = PrettyPrinter().apply(content)