docs(tfhe): add dark market tutorial

Author: yagizsenal

tfhe/Cargo.toml

@@ -182,6 +182,10 @@ required-features = ["shortint", "internal-keycache"]
 name = "boolean_key_sizes"
 required-features = ["boolean", "internal-keycache"]
 
+[[example]]
+name = "dark_market"
+required-features = ["integer", "internal-keycache"]
+
 [[example]]
 name = "shortint_key_sizes"
 required-features = ["shortint", "internal-keycache"]