Change NO_EXPLICIT_VISIBILITY_IN_API_MODE diagnostic range to 'declaration modifiers + name'.

Motivation: missing visibility modifier is an error in visibility modifiers list, so we should highlight this list.
Including a name in the range is convenient for using alt+enter (you don't have to move cursor from name to fun/class/val keyword)

 Also change NO_EXPLICIT_RETURN_TYPE_IN_API_MODE diagnostic range to 'declaration name' to match corresponding IDE inspection.

Fix stylistic problems and typos after review

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.kt

@@ -319,7 +319,7 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
     @Argument(
         value = "-Xexplicit-api",
         valueDescription = "{strict|warning|disable}",
-        description = "Force compiler to report errors an all public API declarations without explicit visibility.\n" +
+        description = "Force compiler to report errors on all public API declarations without explicit visibility or return type.\n" +
                 "Use 'warning' level to issue warnings instead of errors."
     )
     var explicitApi: String by FreezableVar(ExplicitApiMode.DISABLED.state)