Stop nu panicks in math.round on a large decimal value(Most of the time) (#3224)

* Stop crashing when dealing with large numbers in math round

* Fix formatting

* add tests

* just to trigger wasm build

* trigger wasm build

crates/nu-command/src/commands/math/round.rs

@@ -76,9 +76,12 @@ fn round_big_int(val: BigInt) -> Value {
 
 fn round_big_decimal(val: BigDecimal, precision: i64) -> Value {
     if precision > 0 {
-        UntaggedValue::decimal(val.round(precision)).into()
+        UntaggedValue::decimal(val.with_scale(precision + 1).round(precision)).into()
     } else {
-        let (rounded, _) = val.round(precision).as_bigint_and_exponent();
+        let (rounded, _) = val
+            .with_scale(precision + 1)
+            .round(precision)
+            .as_bigint_and_exponent();
         UntaggedValue::int(rounded).into()
     }
 }

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

@@ -1,6 +1,7 @@
 mod avg;
 mod eval;
 mod median;
+mod round;
 mod sum;
 
 use nu_test_support::{nu, pipeline};

crates/nu-command/tests/commands/math/round.rs

@@ -0,0 +1,21 @@
+use nu_test_support::nu;
+
+#[test]
+fn can_round_very_large_numbers() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 18.1372544780074142289927665486772012345 | math round"
+    );
+
+    assert_eq!(actual.out, "18")
+}
+
+#[test]
+fn can_round_very_large_numbers_with_precision() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 18.13725447800741422899276654867720121457878988 | math round -p 10"
+    );
+
+    assert_eq!(actual.out, "18.137254478")
+}