[Proposal] SF-NNNN Search for recurrence in partial ranges

[hristost]

Add new variants to Calendar.RecurrenceRule that allow us to search within partial ranges:

let rule: RecurrenceRule
let event, start, end: Date

// Existing:
rule.recurrences(of: event, in: start..<end) // All occurrences between `start` and `end`, not including `end`

// Proposed:
rule.recurrences(of: event, in: ...end) // All occurrences up to `end`, inclusive
rule.recurrences(of: event, in: ..<end) // All occurrences up to `end`, not inclusive
rule.recurrences(of: event, in: start...) // All occurrences after `start`, inclusive
rule.recurrences(of: event, in: start...end) // All occurrences between `start` and `end`, inclusive

Read the full proposal here