Update syntax doc for show storage units (#32459)

Author: RaigorJiang

docs/document/content/user-manual/shardingsphere-proxy/distsql/syntax/rql/storage-unit-query/show-storage-units.cn.md

@@ -13,7 +13,13 @@ weight = 1
 {{% tab name="语法" %}}
 ```sql
 ShowStorageUnit ::=
-  'SHOW' 'STORAGE' 'UNITS' ('WHERE' 'USAGE_COUNT' '=' usageCount)? ('FROM' databaseName)?
+  'SHOW' 'STORAGE' 'UNITS' showLike? ('WHERE' 'USAGE_COUNT' '=' usageCount)? ('FROM' databaseName)?
+
+showLike ::=
+  'LIKE' likePattern
+
+likePattern ::=
+  string
 
 usageCount ::=
   int

docs/document/content/user-manual/shardingsphere-proxy/distsql/syntax/rql/storage-unit-query/show-storage-units.en.md

@@ -13,7 +13,13 @@ The `SHOW STORAGE UNITS` syntax is used to query the storage units that have bee
 {{% tab name="Grammar" %}}
 ```sql
 ShowStorageUnit ::=
-  'SHOW' 'STORAGE' 'UNITS' ('WHERE' 'USAGE_COUNT' '=' usageCount)? ('FROM' databaseName)?
+  'SHOW' 'STORAGE' 'UNITS' showLike? ('WHERE' 'USAGE_COUNT' '=' usageCount)? ('FROM' databaseName)?
+
+showLike ::=
+  'LIKE' likePattern
+
+likePattern ::=
+  string
 
 usageCount ::=
   int