Add rust-toolchain file so cargo doc will run

ProfLander · ProfLander · commit d2af1df80f3d · 2023-03-02T05:52:36.000Z
diff --git a/rust-toolchain b/rust-toolchain
@@ -0,0 +1,3 @@
+[toolchain]
+channel = "nightly-2022-12-18"
+components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+[toolchain]`
	`2`	`+channel = "nightly-2022-12-18"`
	`3`	`+components = ["rust-src", "rustc-dev", "llvm-tools-preview"]`