move autodiff from EnzymeAD/Enzyme to our rust-lang/Enzyme soft-fork

Author: ZuseZ4

.gitmodules

@@ -45,7 +45,7 @@
 	shallow = true
 [submodule "src/tools/enzyme"]
 	path = src/tools/enzyme
-	url = https://github.com/EnzymeAD/Enzyme.git
+	url = https://github.com/rust-lang/Enzyme.git
 	shallow = true
 [submodule "src/gcc"]
 	path = src/gcc