fmt: fix map missing a comma after enum keys, leading to non parsable code (#13481)

vlib/v/fmt/fmt.v

@@ -2110,16 +2110,25 @@ pub fn (mut f Fmt) map_init(node ast.MapInit) {
 	f.indent++
 	f.comments(node.pre_cmnts)
 	mut max_field_len := 0
+	mut skeys := []string{}
 	for key in node.keys {
-		if key.str().len > max_field_len {
-			max_field_len = key.str().len
+		skey := f.node_str(key).trim_space()
+		skeys << skey
+		if skey.len > max_field_len {
+			max_field_len = skey.len
 		}
 	}
 	for i, key in node.keys {
-		f.expr(key)
+		skey := skeys[i]
+		f.write(skey)
 		f.write(': ')
-		f.write(strings.repeat(` `, max_field_len - key.str().len))
+		f.write(strings.repeat(` `, max_field_len - skey.len))
 		f.expr(node.vals[i])
+		if key is ast.EnumVal && skey.starts_with('.') {
+			// enforce the use of `,` for maps with short enum keys, otherwise there is ambiguity
+			// when the values are struct values, and the code will no longer parse properly
+			f.write(',')
+		}
 		f.comments(node.comments[i], prev_line: node.vals[i].pos().last_line, has_nl: false)
 		f.writeln('')
 	}

vlib/v/fmt/tests/maps_expected.vv

@@ -20,3 +20,8 @@ explicit_init := map[string]string{}
 explicit_init_with_value := {
 	'abc': 0
 }
+
+headers := http.new_header_from_map({
+	.content_type:  'application/json',
+	.authorization: 'Bearer abcdef',
+})

vlib/v/fmt/tests/maps_input.vv

@@ -20,3 +20,8 @@ explicit_init := map[string]string{}
 explicit_init_with_value := map[string]int{
 	'abc': 0
 }
+
+headers := http.new_header_from_map({
+.content_type: 'application/json',
+  .authorization: 'Bearer abcdef'
+})

vlib/v/tests/map_init_with_enum_keys_test.v

@@ -12,7 +12,7 @@ fn test_map_init_with_enum_keys() {
 	mut st := St{}
 
 	st.m = {
-		.ea: 'a'
+		.ea: 'a',
 	}
 
 	println(st.m)