Add and use new Signals struct (#13314)

# Description
This PR introduces a new `Signals` struct to replace our adhoc passing
around of `ctrlc: Option<Arc<AtomicBool>>`. Doing so has a few benefits:
- We can better enforce when/where resetting or triggering an interrupt
is allowed.
- Consolidates `nu_utils::ctrl_c::was_pressed` and other ad-hoc
re-implementations into a single place: `Signals::check`.
- This allows us to add other types of signals later if we want. E.g.,
exiting or suspension.
- Similarly, we can more easily change the underlying implementation if
we need to in the future.
- Places that used to have a `ctrlc` of `None` now use
`Signals::empty()`, so we can double check these usages for correctness
in the future.

crates/nu-command/src/math/abs.rs

@@ -42,10 +42,7 @@ impl Command for SubCommand {
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let head = call.head;
-        input.map(
-            move |value| abs_helper(value, head),
-            engine_state.ctrlc.clone(),
-        )
+        input.map(move |value| abs_helper(value, head), engine_state.signals())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/math/ceil.rs

@@ -41,10 +41,7 @@ impl Command for SubCommand {
         if matches!(input, PipelineData::Empty) {
             return Err(ShellError::PipelineEmpty { dst_span: head });
         }
-        input.map(
-            move |value| operate(value, head),
-            engine_state.ctrlc.clone(),
-        )
+        input.map(move |value| operate(value, head), engine_state.signals())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/math/floor.rs

@@ -41,10 +41,7 @@ impl Command for SubCommand {
         if matches!(input, PipelineData::Empty) {
             return Err(ShellError::PipelineEmpty { dst_span: head });
         }
-        input.map(
-            move |value| operate(value, head),
-            engine_state.ctrlc.clone(),
-        )
+        input.map(move |value| operate(value, head), engine_state.signals())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/math/log.rs

@@ -59,7 +59,7 @@ impl Command for SubCommand {
         let base = base.item;
         input.map(
             move |value| operate(value, head, base),
-            engine_state.ctrlc.clone(),
+            engine_state.signals(),
         )
     }
 

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

@@ -50,7 +50,7 @@ impl Command for SubCommand {
         }
         input.map(
             move |value| operate(value, head, precision_param),
-            engine_state.ctrlc.clone(),
+            engine_state.signals(),
         )
     }
 

crates/nu-command/src/math/sqrt.rs

@@ -41,10 +41,7 @@ impl Command for SubCommand {
         if matches!(input, PipelineData::Empty) {
             return Err(ShellError::PipelineEmpty { dst_span: head });
         }
-        input.map(
-            move |value| operate(value, head),
-            engine_state.ctrlc.clone(),
-        )
+        input.map(move |value| operate(value, head), engine_state.signals())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/math/utils.rs

@@ -1,6 +1,6 @@
 use core::slice;
 use indexmap::IndexMap;
-use nu_protocol::{ast::Call, IntoPipelineData, PipelineData, ShellError, Span, Value};
+use nu_protocol::{ast::Call, IntoPipelineData, PipelineData, ShellError, Signals, Span, Value};
 
 pub fn run_with_function(
     call: &Call,
@@ -92,7 +92,7 @@ pub fn calculate(
         }
         PipelineData::Value(Value::Range { val, .. }, ..) => {
             let new_vals: Result<Vec<Value>, ShellError> = val
-                .into_range_iter(span, None)
+                .into_range_iter(span, Signals::empty())
                 .map(|val| mf(&[val], span, name))
                 .collect();