Box ShellError in Value::Error (#8375)

# Description

Our `ShellError` at the moment has a `std::mem::size_of<ShellError>` of
136 bytes (on AMD64). As a result `Value` directly storing the struct
also required 136 bytes (thanks to alignment requirements).

This change stores the `Value::Error` `ShellError` on the heap.

Pro:
- Value now needs just 80 bytes
- Should be 1 cacheline less (still at least 2 cachelines)

Con:
- More small heap allocations when dealing with `Value::Error`
  - More heap fragmentation
  - Potential for additional required memcopies

# Further code changes

Includes a small refactor of `try` due to a type mismatch in its large
match.

# User-Facing Changes

None for regular users.

Plugin authors may have to update their matches on `Value` if they use
`nu-protocol`

Needs benchmarking to see if there is a benefit in real world workloads.
**Update** small improvements in runtime for workloads with high volume
of values. Significant reduction in maximum resident set size, when many
values are held in memory.

# Tests + Formatting

crates/nu-command/src/date/format.rs

@@ -132,10 +132,10 @@ where
             span,
         },
         Err(_) => Value::Error {
-            error: ShellError::TypeMismatch {
+            error: Box::new(ShellError::TypeMismatch {
                 err_message: "invalid format".to_string(),
                 span,
-            },
+            }),
         },
     }
 }
@@ -152,7 +152,10 @@ fn format_helper(value: Value, formatter: &str, formatter_span: Span, head_span:
             }
         }
         _ => Value::Error {
-            error: ShellError::DatetimeParseError(value.debug_value(), head_span),
+            error: Box::new(ShellError::DatetimeParseError(
+                value.debug_value(),
+                head_span,
+            )),
         },
     }
 }
@@ -177,7 +180,7 @@ fn format_helper_rfc2822(value: Value, span: Span) -> Value {
             }
         }
         _ => Value::Error {
-            error: ShellError::DatetimeParseError(value.debug_value(), span),
+            error: Box::new(ShellError::DatetimeParseError(value.debug_value(), span)),
         },
     }
 }

crates/nu-command/src/date/humanize.rs

@@ -90,7 +90,7 @@ fn helper(value: Value, head: Span) -> Value {
             span: head,
         },
         _ => Value::Error {
-            error: ShellError::DatetimeParseError(value.debug_value(), head),
+            error: Box::new(ShellError::DatetimeParseError(value.debug_value(), head)),
         },
     }
 }

crates/nu-command/src/date/to_record.rs

@@ -156,7 +156,7 @@ fn helper(val: Value, head: Span) -> Value {
         }
         Value::Date { val, span: _ } => parse_date_into_table(Ok(val), head),
         _ => Value::Error {
-            error: DatetimeParseError(val.debug_value(), head),
+            error: Box::new(DatetimeParseError(val.debug_value(), head)),
         },
     }
 }

crates/nu-command/src/date/to_table.rs

@@ -161,7 +161,7 @@ fn helper(val: Value, head: Span) -> Value {
         }
         Value::Date { val, span: _ } => parse_date_into_table(Ok(val), head),
         _ => Value::Error {
-            error: DatetimeParseError(val.debug_value(), head),
+            error: Box::new(DatetimeParseError(val.debug_value(), head)),
         },
     }
 }

crates/nu-command/src/date/to_timezone.rs

@@ -128,7 +128,7 @@ fn helper(value: Value, head: Span, timezone: &Spanned<String>) -> Value {
             _to_timezone(dt.with_timezone(dt.offset()), timezone, head)
         }
         _ => Value::Error {
-            error: ShellError::DatetimeParseError(value.debug_value(), head),
+            error: Box::new(ShellError::DatetimeParseError(value.debug_value(), head)),
         },
     }
 }
@@ -137,10 +137,10 @@ fn _to_timezone(dt: DateTime<FixedOffset>, timezone: &Spanned<String>, span: Spa
     match datetime_in_timezone(&dt, timezone.item.as_str()) {
         Ok(dt) => Value::Date { val: dt, span },
         Err(_) => Value::Error {
-            error: ShellError::TypeMismatch {
+            error: Box::new(ShellError::TypeMismatch {
                 err_message: String::from("invalid time zone"),
                 span: timezone.span,
-            },
+            }),
         },
     }
 }

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

@@ -15,12 +15,12 @@ pub(crate) fn parse_date_from_string(
                 LocalResult::Single(d) => Ok(d),
                 LocalResult::Ambiguous(d, _) => Ok(d),
                 LocalResult::None => Err(Value::Error {
-                    error: ShellError::DatetimeParseError(input.to_string(), span),
+                    error: Box::new(ShellError::DatetimeParseError(input.to_string(), span)),
                 }),
             }
         }
         Err(_) => Err(Value::Error {
-            error: ShellError::DatetimeParseError(input.to_string(), span),
+            error: Box::new(ShellError::DatetimeParseError(input.to_string(), span)),
         }),
     }
 }