minor: make dict_from_values public (#17376)

* minor: make dict_from_values public

* Update datafusion/common/src/scalar/mod.rs

Co-authored-by: Oleks V <[email protected]>

* fix format

* one more format

---------

Co-authored-by: Oleks V <[email protected]>

Author: parthchandra

datafusion/common/src/scalar/mod.rs

@@ -881,8 +881,21 @@ fn dict_from_scalar<K: ArrowDictionaryKeyType>(
     ))
 }
 
-/// Create a dictionary array representing all the values in values
-fn dict_from_values<K: ArrowDictionaryKeyType>(
+/// Create a `DictionaryArray` from the provided values array.
+///
+/// Each element gets a unique key (`0..N-1`), without deduplication.
+/// Useful for wrapping arrays in dictionary form.
+///
+/// # Input
+/// ["alice", "bob", "alice", null, "carol"]
+///
+/// # Output
+/// `DictionaryArray<Int32>`
+/// {
+///   keys:   [0, 1, 2, 3, 4],
+///   values: ["alice", "bob", "alice", null, "carol"]
+/// }
+pub fn dict_from_values<K: ArrowDictionaryKeyType>(
     values_array: ArrayRef,
 ) -> Result<ArrayRef> {
     // Create a key array with `size` elements of 0..array_len for all