[DOCS] to_char(): 'FM' also suppresses *trailing* zeroes

In Table 9-27. "Template Pattern Modifiers for Numeric Formatting" it says:

FM | prefix fill mode (suppress leading zeroes and padding blanks) | FM9999

https://www.postgresql.org/docs/current/static/functions-formatting.html#FUNCTIONS-FORMATTING-NUMERICMOD-TABLE

In fact, 'FM' also suppresses *trailing* zeroes after the comma. To fix, this might be changed to:

   suppress insignificant zeroes and padding blanks

Or:

   suppress padding zeroes and blanks

Regards
Erwin Brandstetter