[xiaomi_en] Add MIX Fold & POCO X3 Pro India

CHANGELOG_en.md

@@ -1,4 +1,6 @@
 # CHANGELOG
+## 2021-03-30
+- `xiaomi_en` India varient POCO X3 Pro and Mi MIX Fold has been added.
 ## 2021-03-29
 - `oneplus_en` OnePlus 9 series have been added (9R's codename needs update).
 - `realme_en` Realme GT Neo has been added.

brands/xiaomi_en.md

@@ -345,6 +345,10 @@
 
 `M1810E5GG`: Mi MIX 3 5G
 
+**[`J18`] Mi MIX Fold (`cetus`):**
+
+`M2011J18C`: Mi MIX Fold China
+
 **[`B3`] Mi Max (`hydrogen`):**
 
 `2016002`: Mi Max Global
@@ -1087,6 +1091,10 @@
 
 `M2102J20SG`: POCO X3 Pro Global
 
+**[`J20S`] POCO X3 Pro (`bhima`):**
+
+`M2102J20SI`: POCO X3 Pro India
+
 **[`J19P`] POCO M2 (`shiva`):**
 
 `M2004J19PI`: POCO M2 India