Add command_prelude module (#12291)

# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
    ShellError, Signature, Span, Type, Value,
};
```

This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
    ast::{Call, CellPath},
    engine::{Command, EngineState, Stack},
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
    PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```

This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.

crates/nu-command/src/formats/to/command.rs

@@ -1,7 +1,4 @@
-use nu_engine::get_full_help;
-use nu_protocol::ast::Call;
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, IntoPipelineData, PipelineData, ShellError, Signature, Type, Value};
+use nu_engine::{command_prelude::*, get_full_help};
 
 #[derive(Clone)]
 pub struct To;

crates/nu-command/src/formats/to/csv.rs

@@ -1,11 +1,6 @@
 use crate::formats::to::delimited::to_delimited_data;
-use nu_engine::CallExt;
-use nu_protocol::ast::Call;
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Config, Example, PipelineData, ShellError, Signature, Span, Spanned, SyntaxShape,
-    Type, Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::Config;
 
 #[derive(Clone)]
 pub struct ToCsv;

crates/nu-command/src/formats/to/delimited.rs

@@ -1,8 +1,7 @@
 use csv::{Writer, WriterBuilder};
 use nu_cmd_base::formats::to::delimited::merge_descriptors;
 use nu_protocol::{Config, IntoPipelineData, PipelineData, Record, ShellError, Span, Value};
-use std::collections::VecDeque;
-use std::error::Error;
+use std::{collections::VecDeque, error::Error};
 
 fn from_value_to_delimited_string(
     value: &Value,

crates/nu-command/src/formats/to/json.rs

@@ -1,10 +1,5 @@
-use nu_engine::CallExt;
-use nu_protocol::ast::{Call, PathMember};
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape, Type,
-    Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::ast::PathMember;
 
 #[derive(Clone)]
 pub struct ToJson;

crates/nu-command/src/formats/to/md.rs

@@ -1,12 +1,7 @@
-use indexmap::map::IndexMap;
+use indexmap::IndexMap;
 use nu_cmd_base::formats::to::delimited::merge_descriptors;
-use nu_engine::CallExt;
-use nu_protocol::ast::Call;
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Config, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Type,
-    Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::Config;
 
 #[derive(Clone)]
 pub struct ToMd;

crates/nu-command/src/formats/to/nuon.rs

@@ -1,14 +1,8 @@
 use core::fmt::Write;
 use fancy_regex::Regex;
-use nu_engine::get_columns;
-use nu_engine::CallExt;
+use nu_engine::{command_prelude::*, get_columns};
 use nu_parser::escape_quote_string;
-use nu_protocol::ast::{Call, RangeInclusion};
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, SyntaxShape,
-    Type, Value,
-};
+use nu_protocol::ast::RangeInclusion;
 use once_cell::sync::Lazy;
 
 #[derive(Clone)]

crates/nu-command/src/formats/to/text.rs

@@ -1,10 +1,6 @@
 use chrono_humanize::HumanTime;
-use nu_protocol::{
-    ast::Call,
-    engine::{Command, EngineState, Stack},
-    format_duration, format_filesize_from_conf, Category, Config, Example, IntoPipelineData,
-    ListStream, PipelineData, RawStream, ShellError, Signature, Type, Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::{format_duration, format_filesize_from_conf, Config, ListStream, RawStream};
 
 #[derive(Clone)]
 pub struct ToText;

crates/nu-command/src/formats/to/toml.rs

@@ -1,9 +1,6 @@
 use chrono::SecondsFormat;
-use nu_protocol::ast::{Call, PathMember};
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Type, Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::ast::PathMember;
 
 #[derive(Clone)]
 pub struct ToToml;

crates/nu-command/src/formats/to/tsv.rs

@@ -1,10 +1,6 @@
 use crate::formats::to::delimited::to_delimited_data;
-use nu_engine::CallExt;
-use nu_protocol::ast::Call;
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Config, Example, PipelineData, ShellError, Signature, Span, Type, Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::Config;
 
 #[derive(Clone)]
 pub struct ToTsv;

crates/nu-command/src/formats/to/xml.rs

@@ -1,16 +1,12 @@
 use crate::formats::nu_xml_format::{COLUMN_ATTRS_NAME, COLUMN_CONTENT_NAME, COLUMN_TAG_NAME};
 use indexmap::IndexMap;
-use nu_engine::CallExt;
-use nu_protocol::ast::Call;
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, Record, ShellError, Signature, Span,
-    Spanned, SyntaxShape, Type, Value,
+use nu_engine::command_prelude::*;
+
+use quick_xml::{
+    escape,
+    events::{BytesEnd, BytesStart, BytesText, Event},
 };
-use quick_xml::escape;
-use quick_xml::events::{BytesEnd, BytesStart, BytesText, Event};
-use std::borrow::Cow;
-use std::io::Cursor;
+use std::{borrow::Cow, io::Cursor};
 
 #[derive(Clone)]
 pub struct ToXml;

crates/nu-command/src/formats/to/yaml.rs

@@ -1,8 +1,5 @@
-use nu_protocol::ast::{Call, PathMember};
-use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Type, Value,
-};
+use nu_engine::command_prelude::*;
+use nu_protocol::ast::PathMember;
 
 #[derive(Clone)]
 pub struct ToYaml;