in for, loop, while, auto print final value in each iteration (#7433)

# Description

Fixes: #7404 
Fixes: #7402 

## About change
In `eval_block`, all pipelines(or called statements?) result will be
printed except the last one, the last one is returned by `eval_block`
function.

So if we want to print the last statement in eval block, we just need to
print that value.

# User-Facing Changes

### for
```
❯ for _ in 1..2 { echo "a" }
a
a
```

### while
```
❯ mut x = 1; while $x < 3 { $x = $x + 1; echo bb; }
bb
bb
```

### loop
```
❯ mut total = 0; loop {
∙     if $total > 1 {
∙         break
∙     } else {
∙         $total += 1
∙     }
∙     echo 3
∙ }
3
3
```

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
  - `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/core_commands/for_.rs

@@ -118,7 +118,7 @@ impl Command for For {
                             return Err(err);
                         }
                         Ok(pipeline) => {
-                            pipeline.into_value(head);
+                            let _ = pipeline.print(&engine_state, stack, false, false)?;
                         }
                     }
                 }
@@ -157,7 +157,7 @@ impl Command for For {
                             return Err(err);
                         }
                         Ok(pipeline) => {
-                            pipeline.into_value(head);
+                            let _ = pipeline.print(&engine_state, stack, false, false)?;
                         }
                     }
                 }

crates/nu-command/src/core_commands/loop_.rs

@@ -69,7 +69,7 @@ impl Command for Loop {
                     return Err(err);
                 }
                 Ok(pipeline) => {
-                    pipeline.into_value(call.head);
+                    let _ = pipeline.print(engine_state, stack, false, false)?;
                 }
             }
         }

crates/nu-command/src/core_commands/while_.rs

@@ -77,7 +77,7 @@ impl Command for While {
                                 return Err(err);
                             }
                             Ok(pipeline) => {
-                                pipeline.into_value(call.head);
+                                let _ = pipeline.print(engine_state, stack, false, false)?;
                             }
                         }
                     } else {

crates/nu-command/tests/commands/for_.rs

@@ -0,0 +1,16 @@
+use nu_test_support::nu;
+
+#[test]
+fn for_auto_print_in_each_iteration() {
+    let actual = nu!(
+        cwd: ".",
+        r#"
+        for i in 1..2 {
+            echo 1
+        }"#
+    );
+    // Note: nu! macro auto repalce "\n" and "\r\n" with ""
+    // so our output will be `11`
+    // that's ok, our main concern is it auto print value in each iteration.
+    assert_eq!(actual.out, "11");
+}

crates/nu-command/tests/commands/loop_.rs

@@ -0,0 +1,22 @@
+use nu_test_support::nu;
+
+#[test]
+fn loop_auto_print_in_each_iteration() {
+    let actual = nu!(
+        cwd: ".",
+        r#"
+        mut total = 0;
+        loop {
+            if $total == 3 {
+                break;
+            } else {
+                $total += 1;
+            }
+            echo 1
+        }"#
+    );
+    // Note: nu! macro auto repalce "\n" and "\r\n" with ""
+    // so our output will be `111`
+    // that's ok, our main concern is it auto print value in each iteration.
+    assert_eq!(actual.out, "111");
+}

crates/nu-command/tests/commands/mod.rs

@@ -24,6 +24,7 @@ mod export_def;
 mod find;
 mod first;
 mod flatten;
+mod for_;
 mod format;
 mod g;
 mod get;
@@ -41,6 +42,7 @@ mod last;
 mod length;
 mod let_;
 mod lines;
+mod loop_;
 mod ls;
 mod math;
 mod merge;

crates/nu-command/tests/commands/while_.rs

@@ -9,3 +9,15 @@ fn while_sum() {
 
     assert_eq!(actual.out, "55");
 }
+
+#[test]
+fn while_auto_print_in_each_iteration() {
+    let actual = nu!(
+        cwd: ".",
+        "mut total = 0; while $total < 2 { $total = $total + 1; echo 1 }"
+    );
+    // Note: nu! macro auto repalce "\n" and "\r\n" with ""
+    // so our output will be `11`
+    // that's ok, our main concern is it auto print value in each iteration.
+    assert_eq!(actual.out, "11");
+}