Remove needless return (#597)

src/cst/matchers.rs

@@ -4,6 +4,6 @@ use libcst_native::Module;
 pub fn match_module(module_text: &str) -> Result<Module> {
     match libcst_native::parse_module(module_text, None) {
         Ok(module) => Ok(module),
-        Err(_) => return Err(anyhow::anyhow!("Failed to extract CST from source.")),
+        Err(_) => Err(anyhow::anyhow!("Failed to extract CST from source.")),
     }
 }