Clarify that remote paths carry literal filesystem names

sdk/wit/filesystem.wit

@@ -81,7 +81,8 @@ interface host {
 
 /// Filesystem operations for one connection. Paths are absolute within its
 /// root, starting with `/`; they are never local OS paths or resource URIs.
-/// Dot segments, backslashes, percent escapes, colons, and controls are invalid.
+/// Colons and percent signs are literal; paths must never be URL-decoded.
+/// Dot segments, backslashes, and controls are invalid.
 /// Every invocation is bounded by host fuel, memory, time, and cancellation.
 interface provider {
     use host.{setting};