Convert ShellError::DatetimeParseError to named fields (#10991)

# Description

Part of #10700

# User-Facing Changes

None

# Tests + Formatting

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting

N/A

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

@@ -79,7 +79,10 @@ fn helper(value: Value, head: Span) -> Value {
         }
         Value::Date { val, .. } => Value::string(humanize_date(val), head),
         _ => Value::error(
-            ShellError::DatetimeParseError(value.debug_value(), head),
+            ShellError::DatetimeParseError {
+                msg: value.debug_value(),
+                span: head,
+            },
             head,
         ),
     }

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

@@ -121,7 +121,13 @@ fn helper(val: Value, head: Span) -> Value {
             parse_date_into_table(n, head)
         }
         Value::Date { val, .. } => parse_date_into_table(val, head),
-        _ => Value::error(DatetimeParseError(val.debug_value(), head), head),
+        _ => Value::error(
+            DatetimeParseError {
+                msg: val.debug_value(),
+                span: head,
+            },
+            head,
+        ),
     }
 }
 

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

@@ -120,7 +120,13 @@ fn helper(val: Value, head: Span) -> Value {
             parse_date_into_table(n, head)
         }
         Value::Date { val, .. } => parse_date_into_table(val, head),
-        _ => Value::error(DatetimeParseError(val.debug_value(), head), head),
+        _ => Value::error(
+            DatetimeParseError {
+                msg: val.debug_value(),
+                span: head,
+            },
+            head,
+        ),
     }
 }
 

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

@@ -122,7 +122,10 @@ fn helper(value: Value, head: Span, timezone: &Spanned<String>) -> Value {
             _to_timezone(dt.with_timezone(dt.offset()), timezone, head)
         }
         _ => Value::error(
-            ShellError::DatetimeParseError(value.debug_value(), head),
+            ShellError::DatetimeParseError {
+                msg: value.debug_value(),
+                span: head,
+            },
             head,
         ),
     }

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

@@ -15,13 +15,19 @@ pub(crate) fn parse_date_from_string(
                 LocalResult::Single(d) => Ok(d),
                 LocalResult::Ambiguous(d, _) => Ok(d),
                 LocalResult::None => Err(Value::error(
-                    ShellError::DatetimeParseError(input.to_string(), span),
+                    ShellError::DatetimeParseError {
+                        msg: input.into(),
+                        span,
+                    },
                     span,
                 )),
             }
         }
         Err(_) => Err(Value::error(
-            ShellError::DatetimeParseError(input.to_string(), span),
+            ShellError::DatetimeParseError {
+                msg: input.into(),
+                span,
+            },
             span,
         )),
     }