Update dimensions.md (#5314)

Now there are 3 dimension types rather than 2

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website/docs/docs/build/dimensions.md

@@ -79,8 +79,7 @@ semantic_model:
 ```
 
 ## Dimensions types
-
-Dimensions have 2 types. This section further explains the definitions and provides examples.
+This section further explains the dimension definitions, along with examples. Dimensions have the following types:
 
 - [Dimensions types](#dimensions-types)
   - [Categorical](#categorical)