[FR]: Fix compilation errors in Chip.md example

Describe the problem

The multiple-selection code example in Chip.md has two errors:

1. filter.name called on a String (String has no .name property)
2. Assignment to unionSelected which is never declared (the variable is selectedFilters)

Describe the solution

Fix both lines:

text = filter,
selectedFilters = if (selected) selectedFilters - filter else selectedFilters + filter

Additional context

Priority: High. Effort: XS.