Minor: let 'Renderer'-helper return more specific type

This allows to easily re-use other renderers from 'Renderer'-block
(previously, one had to declare 'ContextDependentRenderer' just to get
hold of 'RenderingContext' just to call 'render(O, RenderingContext)'
from DiagnosticParameterRenderer, which would be unused anyways)

This commit introduces more specific subtype,
'ContextIndependentParameterRenderer', which exposes 'render(O)' method
for easy re-use.

Several (ab)uses of 'ContextDependentRenderer' have been removed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/highlighter/IdeRenderers.kt

@@ -86,8 +86,8 @@ object IdeRenderers {
     }
 
     @JvmField
-    val HTML_THROWABLE = ContextDependentRenderer<Throwable> { throwable, context ->
-        Renderers.THROWABLE.render(throwable, context).replace("\n", "<br/>")
+    val HTML_THROWABLE = Renderer<Throwable> { throwable ->
+        Renderers.THROWABLE.render(throwable).replace("\n", "<br/>")
     }
 
     @JvmField