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-table/src/common.rs

@@ -1,10 +1,8 @@
-use nu_color_config::{Alignment, StyleComputer, TextStyle};
-use nu_protocol::{Config, FooterMode, ShellError, Span, Value};
-use nu_protocol::{TableMode, TrimStrategy};
-
 use crate::{
     clean_charset, colorize_space_str, string_wrap, NuTableConfig, TableOutput, TableTheme,
 };
+use nu_color_config::{Alignment, StyleComputer, TextStyle};
+use nu_protocol::{Config, FooterMode, ShellError, Span, TableMode, TrimStrategy, Value};
 
 pub type NuText = (String, TextStyle);
 pub type TableResult = Result<Option<TableOutput>, ShellError>;

crates/nu-table/src/table.rs

@@ -3,8 +3,7 @@ use nu_ansi_term::Style;
 use nu_color_config::TextStyle;
 use nu_protocol::TrimStrategy;
 use nu_utils::strip_ansi_unlikely;
-use std::cmp::min;
-use std::collections::HashMap;
+use std::{cmp::min, collections::HashMap};
 use tabled::{
     builder::Builder,
     grid::{

crates/nu-table/src/types/collapse.rs

@@ -1,14 +1,10 @@
+use crate::{
+    common::{get_index_style, load_theme, nu_value_to_string_clean},
+    StringResult, TableOpts, UnstructuredTable,
+};
 use nu_color_config::StyleComputer;
 use nu_protocol::{Config, Record, TableMode, Value};
 
-use crate::UnstructuredTable;
-
-use crate::common::nu_value_to_string_clean;
-use crate::{
-    common::{get_index_style, load_theme},
-    StringResult, TableOpts,
-};
-
 pub struct CollapsedTable;
 
 impl CollapsedTable {

crates/nu-table/src/types/expanded.rs

@@ -1,11 +1,3 @@
-use std::cmp::max;
-use std::collections::HashMap;
-
-use nu_color_config::{Alignment, StyleComputer, TextStyle};
-use nu_engine::column::get_columns;
-use nu_protocol::{Config, Record, ShellError, Span, Value};
-use tabled::grid::config::Position;
-
 use crate::{
     common::{
         create_nu_table_config, error_sign, get_header_style, get_index_style, load_theme,
@@ -16,6 +8,11 @@ use crate::{
     types::has_index,
     NuTable, NuTableCell, TableOpts, TableOutput,
 };
+use nu_color_config::{Alignment, StyleComputer, TextStyle};
+use nu_engine::column::get_columns;
+use nu_protocol::{Config, Record, ShellError, Span, Value};
+use std::{cmp::max, collections::HashMap};
+use tabled::grid::config::Position;
 
 #[derive(Debug, Clone)]
 pub struct ExpandedTable {

crates/nu-table/src/types/general.rs

@@ -1,7 +1,4 @@
-use nu_color_config::TextStyle;
-use nu_engine::column::get_columns;
-use nu_protocol::{Config, Record, ShellError, Value};
-
+use super::has_index;
 use crate::{
     clean_charset, colorize_space,
     common::{
@@ -10,8 +7,9 @@ use crate::{
     },
     NuTable, NuTableCell, StringResult, TableOpts, TableOutput, TableResult,
 };
-
-use super::has_index;
+use nu_color_config::TextStyle;
+use nu_engine::column::get_columns;
+use nu_protocol::{Config, Record, ShellError, Value};
 
 pub struct JustTable;
 

crates/nu-table/src/types/mod.rs

@@ -2,15 +2,14 @@ mod collapse;
 mod expanded;
 mod general;
 
-use std::sync::{atomic::AtomicBool, Arc};
-
 pub use collapse::CollapsedTable;
 pub use expanded::ExpandedTable;
 pub use general::JustTable;
-use nu_color_config::StyleComputer;
-use nu_protocol::{Config, Span, TableIndexMode, TableMode};
 
 use crate::{common::INDEX_COLUMN_NAME, NuTable};
+use nu_color_config::StyleComputer;
+use nu_protocol::{Config, Span, TableIndexMode, TableMode};
+use std::sync::{atomic::AtomicBool, Arc};
 
 pub struct TableOutput {
     pub table: NuTable,

crates/nu-table/src/unstructured_table.rs

@@ -1,3 +1,4 @@
+use crate::{string_width, string_wrap, TableTheme};
 use nu_color_config::StyleComputer;
 use nu_protocol::{Config, Record, Span, Value};
 use tabled::{
@@ -10,8 +11,6 @@ use tabled::{
     tables::{PoolTable, TableValue},
 };
 
-use crate::{string_width, string_wrap, TableTheme};
-
 /// UnstructuredTable has a recursive table representation of nu_protocol::Value.
 ///
 /// It doesn't support alignment and a proper width control.

crates/nu-table/tests/constrains.rs

@@ -1,9 +1,8 @@
 mod common;
 
+use common::{create_row, test_table, TestCase};
 use nu_protocol::TrimStrategy;
 use nu_table::{NuTable, NuTableConfig, TableTheme as theme};
-
-use common::{create_row, test_table, TestCase};
 use tabled::grid::records::vec_records::CellInfo;
 
 #[test]