Update VariantEncoding.md

Co-authored-by: Gang Wu <ustcwg@gmail.com>

Author: aihuaxu

VariantEncoding.md

@@ -435,7 +435,7 @@ Similarly, user expressions operating on an *int8* value of 1 should behave the
 
 *Decimal table*
 
-| Decimal Precision     | Decimal value type | Physical Type  |
+| Decimal Precision     | Decimal value type | Variant Physical Type |
 |-----------------------|--------------------|----------------|
 | 1 <= precision <= 9   | int32              | decimal4       |
 | 10 <= precision <= 18 | int64              | decimal8       |