Function union

union<K, V>(
rangeSet: RangeSet<K, V>,
otherRangeSet: { ranges: Range.Range<K, V>[] },
): RangeSet<K, V>
Computes the union of two range sets, merging overlapping and adjacent ranges.

When ranges overlap or are adjacent with equal values, they are merged into a single range. When ranges overlap with different values, the overlapping portion gets a merged value according to the value merge function, and non-overlapping portions are preserved.
Type Parameters
- K
  The type of range boundaries
- V
  The type of range values
Parameters
- rangeSet: RangeSet<K, V>
  The first range set containing key/value operations and ranges
- otherRangeSet: { ranges: Range.Range<K, V>[] }
  The second range set containing ranges to union with the first
Returns RangeSet<K, V>
A new range set containing the union of both input range sets
Example
```
const rs1 = { ranges: [Range.of(1, 3, 5)], key: Key.closed, value: Value.sum };
const rs2 = { ranges: [Range.of(2, 4, 3)] };
const result = union(rs1, rs2);
// Result contains merged ranges with summed values where they overlap
```
- Defined in union.ts:75