tutorial: update all examples

Author: miaobyte

tutorial/01-hello/main.kv

@@ -1,8 +1,6 @@
 # 01-hello: your first kvlang program
 # Run: kvlang tutorial/01-hello/main.kv
 
-"kvlangrun" -> ./term
-
 def main() -> () {
     print("hello kvlang")
 }

tutorial/02-vars/main.kv

@@ -1,8 +1,6 @@
 # 02-vars: variables and paths
 # Run: kvlang tutorial/02-vars/main.kv
 
-"kvlangrun" -> ./term
-
 def main() -> () {
     42 -> ./x                     // write 42 to path ./x
     print("x =", ./x)             // read from path ./x

tutorial/03-arith/main.kv

@@ -1,8 +1,6 @@
 # 03-arith: arithmetic operations
 # Run: kvlang tutorial/03-arith/main.kv
 
-"kvlangrun" -> ./term
-
 def main() -> () {
     print("add:", 10 + 3)          // 13
     print("sub:", 10 - 3)          // 7

tutorial/04-func/main.kv

@@ -1,8 +1,6 @@
 # 04-func: defining and calling functions
 # Run: kvlang tutorial/04-func/main.kv
 
-"kvlangrun" -> ./term
-
 def add(A: int, B: int) -> (C: int) {
     A + B -> ./C
 }

tutorial/05-if/main.kv

@@ -1,8 +1,6 @@
 # 05-if: conditional logic
 # Run: kvlang tutorial/05-if/main.kv
 
-"kvlangrun" -> ./term
-
 def abs(x: int) -> (r: int) {
     if (x < 0) {
         -x -> ./r

tutorial/06-while/main.kv

@@ -1,8 +1,6 @@
 # 06-while: while loops, break, and continue
 # Run: kvlang tutorial/06-while/main.kv
 
-"kvlangrun" -> ./term
-
 # sum 1 + 2 + ... + n
 def sum_to(n: int) -> (total: int) {
     0 -> ./total

tutorial/07-recursion/main.kv

@@ -1,8 +1,6 @@
 # 07-recursion: recursive functions with TCO
 # Run: kvlang tutorial/07-recursion/main.kv
 
-"kvlangrun" -> ./term
-
 def fib(n: int) -> (a: int, b: int) {
     if (n <= 1) {
         0 -> ./a

tutorial/08-algo/classify.kv

@@ -5,8 +5,6 @@
 # 期望输出:
 #   grade = B
 
-"kvlangrun" -> ./term
-
 def classify(score:int) -> (grade:string) {
     if (score >= 90) {
         "A" -> ./grade

tutorial/08-algo/collatz.kv

@@ -5,8 +5,6 @@
 # 期望输出:
 #   steps = 111
 
-"kvlangrun" -> ./term
-
 def collatz(n:int) -> (steps:int) {
     0 -> ./steps
     while (n > 1) {

tutorial/08-algo/factorial.kv

@@ -5,8 +5,6 @@
 # 期望输出:
 #   fact = 3628800
 
-"kvlangrun" -> ./term
-
 def factorial(n:int) -> (result:int) {
     1 -> ./result
     1 -> ./i