remove REGULAR encoding docs (#3477)

docs/UserGuide/Data-Concept/Encoding.md

@@ -47,12 +47,6 @@ Currently, there are two versions of GORILLA encoding implementation, it is reco
 
 Usage restrictions: When using GORILLA to encode INT32 data, you need to ensure that there is no data point with the value `Integer.MIN_VALUE` in the sequence. When using GORILLA to encode INT64 data, you need to ensure that there is no data point with the value `Long.MIN_VALUE` in the sequence.
 
-* REGULAR
-
-Regular data encoding is more suitable for time encoding regular sequence increasing data (e.g. the timeseries with the same time elapsed between each data point), in which case it's better than TS_2DIFF.
-
-Regular data encoding method is not suitable for the data with fluctuations (irregular data), and TS_2DIFF is recommended to deal with it.
-
 * DICTIONARY
 
 DICTIONARY encoding is lossless. It is suitable for TEXT data with low cardinality (i.e. low number of distinct values). It is not recommended to use it for high-cardinality data. 

docs/zh/UserGuide/Data-Concept/Encoding.md

@@ -47,12 +47,6 @@ GORILLA编码是一种无损编码，它比较适合编码前后值比较接近
 
 使用限制：使用Gorilla编码INT32数据时，需要保证序列中不存在值为`Integer.MIN_VALUE`的数据点；使用Gorilla编码INT64数据时，需要保证序列中不存在值为`Long.MIN_VALUE`的数据点。
 
-* 定频数据编码 (REGULAR)
-
-定频数据编码，仅适用于整型（INT32）和长整型（INT64）的时间列定频数据，且允许数据中有一些点缺失，使用此方法编码定频数据优于二阶差分编码（TS_2DIFF）。
-
-定频数据编码无法用于非定频数据，建议使用二阶差分编码（TS_2DIFF）进行处理。
-
 * 字典编码 （DICTIONARY）
 
 字典编码是一种无损编码。它适合编码基数小的数据（即数据去重后唯一值数量小）。不推荐用于基数大的数据。