docs: migrate lib.errors to doc-comments

src/errors/default.nix

@@ -1,8 +1,13 @@
 lib: {
-  ## Prints a message if the condition is not met. The result of
-  ## the condition is returned.
-  ##
-  ## @notest
-  ## @type Bool -> String -> Bool
+  /**
+    Prints a message if the condition is not met. The result of
+    the condition is returned.
+
+    # Type
+
+    ```
+    trace :: Bool -> String -> Bool
+    ```
+  */
   trace = condition: message: if condition then true else builtins.trace message false;
 }