Update RLCD documentation to simplify usage section

Removed description of implementation details for RLCD.

Signed-off-by: Yujia Zheng <yjzheng19@gmail.com>

Author: kunwuz

docs/source/search_methods_index/Hidden causal representation learning/rlcd.rst

@@ -8,7 +8,6 @@ Algorithm Introduction
 
 RLCD [1]_ learns causal structures with causally-related hidden variables from rank constraints in partially observed linear causal models.
 
-This implementation includes the structure learning part of RLCD from ``scm-identify``. It provides the main RLCD search routine and the rank-test helper used for sample data.
 
 Usage
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