Use imported names in Command::run signatures (#7967)

# Description

_(Thank you for improving Nushell. Please, check our [contributing
guide](../CONTRIBUTING.md) and talk to the core team before making major
changes.)_

I opened this PR to unify the run command method. It's mainly to improve
consistency across the tree.

# User-Facing Changes

None.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/deprecated/str_datetime.rs

@@ -1,7 +1,7 @@
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
-    Category, PipelineData, Signature,
+    Category, PipelineData, ShellError, Signature,
 };
 
 #[derive(Clone)]
@@ -26,7 +26,7 @@ impl Command for StrDatetimeDeprecated {
         _stack: &mut Stack,
         call: &Call,
         _input: PipelineData,
-    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+    ) -> Result<PipelineData, ShellError> {
         Err(nu_protocol::ShellError::DeprecatedCommand(
             self.name().to_string(),
             "into datetime".to_string(),

crates/nu-command/src/deprecated/str_decimal.rs

@@ -1,7 +1,7 @@
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
-    Category, PipelineData, Signature,
+    Category, PipelineData, ShellError, Signature,
 };
 
 #[derive(Clone)]
@@ -26,7 +26,7 @@ impl Command for StrDecimalDeprecated {
         _stack: &mut Stack,
         call: &Call,
         _input: PipelineData,
-    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+    ) -> Result<PipelineData, ShellError> {
         Err(nu_protocol::ShellError::DeprecatedCommand(
             self.name().to_string(),
             "into decimal".to_string(),

crates/nu-command/src/deprecated/str_find_replace.rs

@@ -1,7 +1,7 @@
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
-    Category, PipelineData, Signature,
+    Category, PipelineData, ShellError, Signature,
 };
 
 #[derive(Clone)]
@@ -26,7 +26,7 @@ impl Command for StrFindReplaceDeprecated {
         _stack: &mut Stack,
         call: &Call,
         _input: PipelineData,
-    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+    ) -> Result<PipelineData, ShellError> {
         Err(nu_protocol::ShellError::DeprecatedCommand(
             self.name().to_string(),
             "str replace".to_string(),

crates/nu-command/src/deprecated/str_int.rs

@@ -1,7 +1,7 @@
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
-    Category, PipelineData, Signature,
+    Category, PipelineData, ShellError, Signature,
 };
 
 #[derive(Clone)]
@@ -26,7 +26,7 @@ impl Command for StrIntDeprecated {
         _stack: &mut Stack,
         call: &Call,
         _input: PipelineData,
-    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+    ) -> Result<PipelineData, ShellError> {
         Err(nu_protocol::ShellError::DeprecatedCommand(
             self.name().to_string(),
             "into int".to_string(),