Fix append_text_comment rule to not add an extra space

[jeparlefrancais]

Closes #199

Remove the extra space that is added in front of comments. This makes it possible to generate comments like --!native which are useful in Luau.

• add entry to the changelog

[github-actions]

Coverage after merging fix-append-text-space-padding into main will be

86.09%

Coverage Report for Changed Files

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src/rules
append_text_comment.rs	51.75%	100%	69.23%	50.69%	118–125, 141–154, 160–171, 177–186, 192–201, 207–223, 229–240, 246–253, 259–267, 282–300, 321–328, 331–333, 335–337, 347–348, 350–351, 360–362, 366–368, 37, 370–371, 379, 38, 380, 385–389, 39, 390–393, 40, 406–407, 41, 413–419, 42, 420, 43, 450–455, 482–498, 505–507, 54, 56–59, 72–73