Function parse_iso_datetime 

pub fn parse_iso_datetime(input: &mut &str) -> Result<TimeExpression>

Parse ISO 8601 datetime format.

Supports various ISO datetime formats:

• Date only: 2024-01-15
• Date and time: 2024-01-15T14:30:00
• With timezone: 2024-01-15T14:30:00Z
• With offset: 2024-01-15T14:30:00+02:00
• With fractional seconds: 2024-01-15T14:30:00.123Z

Examples

// Parses: "2024-01-15T14:30:00Z"
// Into: TimeExpression::Absolute(AbsoluteTime { ... })