docs: Add bitmap_to_array doc (#2940)

Author: b41sh

docs/en/sql-reference/20-sql-functions/01-bitmap-functions/bitmap-to-array.md

@@ -0,0 +1,27 @@
+---
+title: BITMAP_TO_ARRAY
+---
+
+Converts a Bitmap into an Array.
+
+## Syntax
+
+```sql
+BITMAP_TO_ARRAY( <bitmap> )
+```
+
+## Return Type
+
+`Array (UInt64)`
+
+## Examples
+
+```sql
+SELECT BITMAP_TO_ARRAY(TO_BITMAP('1, 3, 5'));
+
+╭───────────────────────────────────────╮
+│ bitmap_to_array(to_bitmap('1, 3, 5')) │
+├───────────────────────────────────────┤
+│ [1,3,5]                               │
+╰───────────────────────────────────────╯
+```