docs: rust: update Rust docs output path

The Rust code documentation output path moved from `rust/doc` to
`Documentation/output/rust/rustdoc`, thus update the old reference.

Fixes: 48fadf4 ("docs: Move rustdoc output, cross-reference it")
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

Documentation/rust/general-information.rst

@@ -29,7 +29,7 @@ target with the same invocation used for compilation, e.g.::
 
 To read the docs locally in your web browser, run e.g.::
 
-	xdg-open rust/doc/kernel/index.html
+	xdg-open Documentation/output/rust/rustdoc/kernel/index.html
 
 To learn about how to write the documentation, please see coding-guidelines.rst.