db, json, time, term: change optional to result (#16201)

vlib/sqlite/sqlite.v

@@ -106,7 +106,7 @@ fn C.sqlite3_errmsg(&C.sqlite3) &char
 fn C.sqlite3_free(voidptr)
 
 // connect Opens the connection with a database.
-pub fn connect(path string) ?DB {
+pub fn connect(path string) !DB {
 	db := &C.sqlite3(0)
 	code := C.sqlite3_open(&char(path.str), &db)
 	if code != 0 {
@@ -124,7 +124,7 @@ pub fn connect(path string) ?DB {
 // close Closes the DB.
 // TODO: For all functions, determine whether the connection is
 // closed first, and determine what to do if it is
-pub fn (mut db DB) close() ?bool {
+pub fn (mut db DB) close() !bool {
 	code := C.sqlite3_close(db.conn)
 	if code == 0 {
 		db.is_open = false
@@ -217,7 +217,7 @@ pub fn (db &DB) exec(query string) ([]Row, int) {
 // Execute a query, handle error code
 // Return the first row from the resulting table
 [manualfree]
-pub fn (db &DB) exec_one(query string) ?Row {
+pub fn (db &DB) exec_one(query string) !Row {
 	rows, code := db.exec(query)
 	defer {
 		unsafe { rows.free() }