Handle # and ? characters in directory path

When referencing the current-working-directory, before
it is set by an OSC 7 escape sequence, we ask the OS
for the correct path.  This path was then being parsed
as a URL; where a "#" or "?" character would be
interpreted as the start of a fragment or query
component of a URL -- which is a mistake.

So this change parses the returned directory as such,
where those characters will be treated as a normal
character in the path.

Nothing is changed for the OSC 7 escape sequence case.
In that case, the application must percent-encode the
path before sending, so that those characters are not
misinterpreted.

As per issue #6158 reported by Syntaxheld

mux/src/localpane.rs

@@ -1045,7 +1045,7 @@ impl LocalPane {
         {
             let leader = self.get_leader(policy);
             if let Some(path) = &leader.current_working_dir {
-                return Url::parse(&format!("file://localhost{}", path.display())).ok();
+                return Url::from_directory_path(path).ok();
             }
             return None;
         }
@@ -1055,7 +1055,7 @@ impl LocalPane {
             // Since windows paths typically start with something like C:\,
             // we cannot simply stick `localhost` on the front; we have to
             // omit the hostname otherwise the url parser is unhappy.
-            return Url::parse(&format!("file://{}", fg.cwd.display())).ok();
+            return Url::from_directory_path(fg.cwd).ok();
         }
 
         #[allow(unreachable_code)]