Template patterns for numeric formatting

A sign formatted using SG, PL, or MI is not anchored to the number.

Pattern	Description
`9`	Value with the specified number of digits
`0`	Value with leading zeros
`.`	Decimal point
`,`	Group (thousand) separator
`PR`	Negative value in angle brackets
`S`	Sign anchored to number (uses locale)
`L`	Currency symbol (uses locale)
`D`	Decimal point (uses locale)
`G`	Group separator (uses locale)
`MI`	Minus sign in specified position (if number < 0)
`PL`	Plus sign in specified position (if number > 0)
`SG`	Plus/minus sign in specified position
`RN`	Roman numeral (input between 1 and 3999)
`TH/th`	Ordinal number suffix
`V`	Shift specified number of digits

Usage

A sign formatted using SG, PL, or MI is not anchored to the number. For example:
```
=> SELECT to_char(-12, 'S9999'), to_char(-12, 'MI9999');
 to_char | to_char
---------+---------
   -12   | -  12
(1 row)
```
- TO_CHAR(-12, 'S9999') produces ' -12'
- TO_CHAR(-12, 'MI9999') produces '- 12'
9 results in a value with the same number of digits as there are 9s. If a digit is not available it outputs a space.
TH does not convert values less than zero and does not convert fractional numbers.
V effectively multiplies the input values by 10^n, where n is the number of digits following V. TO_CHAR does not support the use of V combined with a decimal point—for example: 99.9V99.