Have `forc fmt` limit text width to 100 characters

[mohammadfawaz]

Just like rustfmt, have the formatter limit text width to 100 characters. There is probably no need to make this number configurable.

Related: #1209

[eureka-cpu]

Tracking this for swayfmt-v2 with #2001

[mohammadfawaz]

Will close this then as a dup of #2001