[fractal] misc: Add Rust toolchain config file

[Julian Sparber <jsparber src gnome org>]

commit 779c098b70da10c8a30d0df19bbd05e5de2a977c
Author: Kévin Commaille <zecakeh tedomum fr>
Date:   Sat Apr 9 18:22:25 2022 +0200

    misc: Add Rust toolchain config file
    
    Make Rust-Analyzer use the nightly toolchain

 rust-toolchain.toml | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 000000000..8e275b740
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,3 @@
+[toolchain]
+channel = "nightly"
+components = ["rustfmt", "clippy"]