fix(complete): Change ValueHint::Unknown to Other, from AnyPath

`AnyPath` is the documented behavior *but* thats to help when there
isn't much other information.  With us choosing a `ValueHint` based on
the value parser, we are less likely to get benefit from `AnyPath`.

Instead, this will greatly improve cases like Cargo where we offer path
completions on many arguments where it doesn't make sense.

Author: epage

clap_complete/src/engine/complete.rs

@@ -329,10 +329,10 @@ fn complete_arg_value(
         }
     } else {
         match arg.get_value_hint() {
-            clap::ValueHint::Other => {
+            clap::ValueHint::Unknown | clap::ValueHint::Other => {
                 // Should not complete
             }
-            clap::ValueHint::Unknown | clap::ValueHint::AnyPath => {
+            clap::ValueHint::AnyPath => {
                 values.extend(complete_path(value_os, current_dir, &|_| true));
             }
             clap::ValueHint::FilePath => {