1067: minor docs tweak for clarification (#1341)

Added clarification that local devices means "devices mounted on the
local file system"

docs/modules/tiered-storage/pages/overview.adoc

@@ -70,4 +70,4 @@ If both are enabled simultaneously, `InvalidConfigurationException` is thrown du
 - SQL is not supported for the Tiered-Storage-backed maps. `UnsupportedOperationException` is thrown when a SQL query is executed.
 To avoid this, use xref:query:predicate-overview.adoc[Predicate API] instead.
 
-- Dynamic addition of local devices is not supported.
+- Dynamic addition of local devices (i.e. devices mounted on the local file system) is not supported.