fmt: fix weird bug with tabs in string inpertolation

vlib/v/fmt/fmt.v

@@ -88,7 +88,7 @@ fn (mut f Fmt) find_comment(line_nr int) {
 }
 */
 pub fn (mut f Fmt) write(s string) {
-	if !f.buffering || f.is_inside_interp {
+	if !f.buffering {
 		if f.indent > 0 && f.empty_line {
 			if f.indent < tabs.len {
 				f.out.write(tabs[f.indent])
@@ -153,6 +153,10 @@ fn (mut f Fmt) adjust_complete_line() {
 				if f.penalties[j] <= 1 && f.precedences[j] == precedence {
 					sub_expr_end_idx = j
 					break
+				} else if f.precedences[j] < precedence {
+					// we cannot form a sensible subexpression
+					len_sub_expr = C.INT32_MAX
+					break
 				} else {
 					len_sub_expr += f.expr_bufs[j+1].len
 				}

vlib/v/fmt/tests/expressions_expected.vv

@@ -46,6 +46,10 @@ fn main() {
 	if a + b + r * d + a + b + r * d > a + b + r * d + a * b + r {
 		println('ok')
 	}
+	v_str := 'v'
+	s := []string{}
+	s << '	`$v_str`'
+	println(s)
 }
 
 fn gen_str_for_multi_return(mut g gen.Gen, info table.MultiReturn, styp, str_fn_name string) {

vlib/v/fmt/tests/expressions_input.vv

@@ -56,6 +56,10 @@ fn main() {
 		a*b+r {
 		println('ok')
 	}
+	v_str := 'v'
+	s := []string{}
+	s << '	`$v_str`'
+	println(s)
 }
 
 fn gen_str_for_multi_return(mut g gen.Gen,