tracking: postgres-compatible number `to_char` function

[forsaken628]

Summary

16480

https://www.postgresql.org/docs/current/functions-formatting.html

• [x] Data type: int8, int16, int32, int64 #16507
• [x] Data type: float, double #16507
• [ ] Data type: decimal32, decimal64
• [ ] Reuse parsed FormatNode
• [x] Pattern: 9/0/./,/PR/MI/PL/SG/EEEE/literal #16507
• [ ] Pattern: S sign anchored to number (uses locale)
• [ ] Pattern: L currency symbol (uses locale)
• [ ] Pattern: D decimal point (uses locale)
• [ ] Pattern: G group separator (uses locale)
• [ ] Pattern: RN Roman numeral (input between 1 and 3999)
• [ ] Pattern: TH or th ordinal number suffix
• [ ] Pattern: V shift specified number of digits
• [ ] more test
• [ ] doc

[AtlasPilotPuppy]

I would like to take this isue.