fmt: keep new line at both ends of block comment (#8003)

vlib/v/fmt/fmt.v

@@ -1372,7 +1372,7 @@ pub fn (mut f Fmt) comment(node ast.Comment, options CommentsOptions) {
 		x := node.text.trim_left('\x01')
 		if x.contains('\n') {
 			f.writeln('/*')
-			f.writeln(x)
+			f.writeln(x.trim_space())
 			f.write('*/')
 		} else {
 			f.write('/* ${x.trim(' ')} */')
@@ -1397,7 +1397,7 @@ pub fn (mut f Fmt) comment(node ast.Comment, options CommentsOptions) {
 		f.write(out_s)
 		return
 	}
-	lines := node.text.split_into_lines()
+	lines := node.text.trim_space().split_into_lines()
 	f.writeln('/*')
 	for line in lines {
 		f.writeln(line)

vlib/v/fmt/tests/comments_expected.vv

@@ -10,6 +10,15 @@ fn mr_fun() (int, int) {
 }
 
 fn main() {
+	/*
+	block1
+	*/
+	/*
+	block2
+	*/
+	/*
+	block3
+	*/
 	// this is a comment
 	a := 1
 	// and another comment

vlib/v/fmt/tests/comments_input.vv

@@ -7,6 +7,15 @@ fn mr_fun() (int, int) {
 }
 
 fn main() {
+	/* block1
+	*/
+	/*
+	block2 */
+	/*
+
+	block3
+
+	*/
 	a := /* this is a comment */ 1
 	b, c := /* and another comment */ a, /* just to make it worse */ 2
 	d := c // and an extra one

vlib/v/fmt/tests/comments_keep.vv

@@ -43,5 +43,8 @@ fn main() {
 	//////
 	// /
 	// 123
+	/*
+	block
+	*/
 	println('hello world')
 }

vlib/v/scanner/scanner.v

@@ -959,7 +959,7 @@ fn (mut s Scanner) text_scan() token.Token {
 					}
 					s.pos++
 					if s.should_parse_comment() {
-						comment := s.text[start..(s.pos - 1)].trim_space()
+						comment := s.text[start..(s.pos - 1)].trim(' ')
 						return s.new_token(.comment, comment, comment.len + 4)
 					}
 					// Skip if not in fmt mode