Convert ShellError::UnsupportedInput to named fields (#10971)

# Description

This is easy to do with rust-analyzer, but I didn't want to just pump
these all out without feedback.

Part of #10700

# User-Facing Changes

None

# Tests + Formatting

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

# After Submitting

N/A

---------

Co-authored-by: Stefan Holderbach <sholderbach@users.noreply.github.com>

crates/nu-command/src/strings/encode_decode/base64.rs

@@ -127,13 +127,12 @@ fn action(
                 Value::string(std::str::from_utf8(&enc_vec).unwrap_or(""), command_span)
             }
             ActionType::Decode => Value::error(
-                ShellError::UnsupportedInput(
-                    "Binary data can only be encoded".to_string(),
-                    "value originates from here".into(),
-                    command_span,
-                    // This line requires the Value::Error {} match above.
-                    input.span(),
-                ),
+                ShellError::UnsupportedInput {
+                    msg: "Binary data can only be encoded".to_string(),
+                    input: "value originates from here".into(),
+                    msg_span: command_span,
+                    input_span: input.span(),
+                },
                 command_span,
             ),
         },

crates/nu-command/src/strings/encode_decode/decode.rs

@@ -99,12 +99,12 @@ documentation link at https://docs.rs/encoding_rs/latest/encoding_rs/#statics"#
             }
             // This should be more precise, but due to difficulties in getting spans
             // from PipelineData::ListData, this is as it is.
-            _ => Err(ShellError::UnsupportedInput(
-                "non-binary input".into(),
-                "value originates from here".into(),
-                head,
-                input.span().unwrap_or(head),
-            )),
+            _ => Err(ShellError::UnsupportedInput {
+                msg: "non-binary input".into(),
+                input: "value originates from here".into(),
+                msg_span: head,
+                input_span: input.span().unwrap_or(head),
+            }),
         }
     }
 }

crates/nu-command/src/strings/encode_decode/encode.rs

@@ -113,12 +113,12 @@ documentation link at https://docs.rs/encoding_rs/latest/encoding_rs/#statics"#
             }
             // This should be more precise, but due to difficulties in getting spans
             // from PipelineData::ListStream, this is as it is.
-            _ => Err(ShellError::UnsupportedInput(
-                "non-string input".into(),
-                "value originates from here".into(),
-                head,
-                input.span().unwrap_or(head),
-            )),
+            _ => Err(ShellError::UnsupportedInput {
+                msg: "non-string input".into(),
+                input: "value originates from here".into(),
+                msg_span: head,
+                input_span: input.span().unwrap_or(head),
+            }),
         }
     }
 }

crates/nu-command/src/strings/encode_decode/encoding.rs

@@ -12,12 +12,12 @@ pub fn detect_encoding_name(
     //Guess(TLD=None(usually used in HTML), Allow_UTF8=True)
     let (encoding, is_certain) = detector.guess_assess(None, true);
     if !is_certain {
-        return Err(ShellError::UnsupportedInput(
-            "Input contains unknown encoding, try giving a encoding name".into(),
-            "value originates from here".into(),
-            head,
-            input,
-        ));
+        return Err(ShellError::UnsupportedInput {
+            msg: "Input contains unknown encoding, try giving a encoding name".into(),
+            input: "value originates from here".into(),
+            msg_span: head,
+            input_span: input,
+        });
     }
     Ok(encoding)
 }

crates/nu-command/src/strings/str_/substring.rs

@@ -191,13 +191,12 @@ fn action(input: &Value, args: &Arguments, head: Span) -> Value {
         // Propagate errors by explicitly matching them before the final case.
         Value::Error { .. } => input.clone(),
         other => Value::error(
-            ShellError::UnsupportedInput(
-                "Only string values are supported".into(),
-                format!("input type: {:?}", other.get_type()),
-                head,
-                // This line requires the Value::Error match above.
-                other.span(),
-            ),
+            ShellError::UnsupportedInput {
+                msg: "Only string values are supported".into(),
+                input: format!("input type: {:?}", other.get_type()),
+                msg_span: head,
+                input_span: other.span(),
+            },
             head,
         ),
     }

crates/nu-command/src/strings/str_/trim/trim_.rs

@@ -198,18 +198,15 @@ fn action(input: &Value, arg: &Arguments, head: Span) -> Value {
                     }
                     _ => input.clone(),
                 },
-                ActionMode::Local => {
-                    Value::error(
-                        ShellError::UnsupportedInput(
-                            "Only string values are supported".into(),
-                            format!("input type: {:?}", other.get_type()),
-                            head,
-                            // This line requires the Value::Error match above.
-                            other.span(),
-                        ),
-                        head,
-                    )
-                }
+                ActionMode::Local => Value::error(
+                    ShellError::UnsupportedInput {
+                        msg: "Only string values are supported".into(),
+                        input: format!("input type: {:?}", other.get_type()),
+                        msg_span: head,
+                        input_span: other.span(),
+                    },
+                    head,
+                ),
             }
         }
     }