Follow API guidelines for public types (#12283)

# Description
Follow the [API guideline naming
conventions](https://rust-lang.github.io/api-guidelines/naming.html)
also for our externally exposed types

(See
[`clippy::wrong_self_convention`](https://rust-lang.github.io/rust-clippy/master/index.html#/wrong_self_convention)
with [`avoid-breaking-exported-api =
false`](https://doc.rust-lang.org/clippy/lint_configuration.html#avoid-breaking-exported-api)
)

Also be a good citizen around doccomments

- **Fix `Unit::to_value` to `Unit::build_value`**
- **Fix `PipelineData::is_external_failed` to `check_external_failed`**
- **Fix doccomment on `check_external_failed`**
- **Fix `Value::into_config` naming to `parse_as_config`**
- **Document `Value::parse_as_config`**

# Plugin-Author-Facing Changes
See renames above

crates/nu-cmd-lang/src/core_commands/try_.rs

@@ -65,7 +65,7 @@ impl Command for Try {
             }
             // external command may fail to run
             Ok(pipeline) => {
-                let (pipeline, external_failed) = pipeline.is_external_failed();
+                let (pipeline, external_failed) = pipeline.check_external_failed();
                 if external_failed {
                     // Because external command errors aren't "real" errors,
                     // (unless do -c is in effect)

crates/nu-engine/src/env.rs

@@ -353,7 +353,7 @@ pub fn find_in_dirs_env(
 /// is the canonical way to fetch config at runtime when you have Stack available.
 pub fn get_config(engine_state: &EngineState, stack: &Stack) -> Config {
     if let Some(mut config_record) = stack.get_env_var(engine_state, "config") {
-        config_record.into_config(engine_state.get_config()).0
+        config_record.parse_as_config(engine_state.get_config()).0
     } else {
         engine_state.get_config().clone()
     }

crates/nu-engine/src/eval.rs

@@ -314,7 +314,7 @@ pub fn eval_expression_with_input<D: DebugContext>(
 
 // Try to catch and detect if external command runs to failed.
 fn might_consume_external_result(input: PipelineData) -> (PipelineData, bool) {
-    input.is_external_failed()
+    input.check_external_failed()
 }
 
 fn eval_redirection<D: DebugContext>(

crates/nu-protocol/src/ast/unit.rs

@@ -32,7 +32,7 @@ pub enum Unit {
 }
 
 impl Unit {
-    pub fn to_value(&self, size: i64, span: Span) -> Result<Value, ShellError> {
+    pub fn build_value(self, size: i64, span: Span) -> Result<Value, ShellError> {
         match self {
             Unit::Byte => Ok(Value::filesize(size, span)),
             Unit::Kilobyte => Ok(Value::filesize(size * 1000, span)),

crates/nu-protocol/src/config/mod.rs

@@ -172,9 +172,16 @@ impl Default for Config {
 }
 
 impl Value {
-    pub fn into_config(&mut self, config: &Config) -> (Config, Option<ShellError>) {
+    /// Parse the given [`Value`] as a configuration record, and recover encountered mistakes
+    ///
+    /// If any given (sub)value is detected as impossible, this value will be restored to the value
+    /// in `existing_config`, thus mutates `self`.
+    ///
+    /// Returns a new [`Config`] (that is in a valid state) and if encountered the [`ShellError`]
+    /// containing all observed inner errors.
+    pub fn parse_as_config(&mut self, existing_config: &Config) -> (Config, Option<ShellError>) {
         // Clone the passed-in config rather than mutating it.
-        let mut config = config.clone();
+        let mut config = existing_config.clone();
 
         // Vec for storing errors. Current Nushell behaviour (Dec 2022) is that having some typo
         // like `"always_trash": tru` in your config.nu's `$env.config` record shouldn't abort all

crates/nu-protocol/src/engine/engine_state.rs

@@ -295,7 +295,7 @@ impl EngineState {
                             // Don't insert the record as the "config" env var as-is.
                             // Instead, mutate a clone of it with into_config(), and put THAT in env_vars.
                             let mut new_record = v.clone();
-                            let (config, error) = new_record.into_config(&self.config);
+                            let (config, error) = new_record.parse_as_config(&self.config);
                             self.config = Arc::new(config);
                             config_updated = true;
                             env_vars.insert(k, new_record);

crates/nu-protocol/src/engine/pattern_match.rs

@@ -145,7 +145,7 @@ impl Matcher for Pattern {
                         let span = unit.span;
 
                         if let Expr::Int(size) = amount.expr {
-                            match &unit.item.to_value(size, span) {
+                            match &unit.item.build_value(size, span) {
                                 Ok(v) => v == value,
                                 _ => false,
                             }

crates/nu-protocol/src/eval_base.rs

@@ -136,7 +136,7 @@ pub trait Eval {
             Expr::String(s) => Ok(Value::string(s.clone(), expr.span)),
             Expr::Nothing => Ok(Value::nothing(expr.span)),
             Expr::ValueWithUnit(e, unit) => match Self::eval::<D>(state, mut_state, e)? {
-                Value::Int { val, .. } => unit.item.to_value(val, unit.span),
+                Value::Int { val, .. } => unit.item.build_value(val, unit.span),
                 x => Err(ShellError::CantConvert {
                     to_type: "unit value".into(),
                     from_type: x.get_type().to_string(),

crates/nu-protocol/src/pipeline_data/mod.rs

@@ -699,14 +699,16 @@ impl PipelineData {
         }
     }
 
-    /// Try to catch external stream exit status and detect if it runs to failed.
+    /// Try to catch the external stream exit status and detect if it failed.
     ///
-    /// This is useful to commands with semicolon, we can detect errors early to avoid
-    /// commands after semicolon running.
+    /// This is useful for external commands with semicolon, we can detect errors early to avoid
+    /// commands after the semicolon running.
     ///
-    /// Returns self and a flag indicates if the external stream runs to failed.
-    /// If `self` is not Pipeline::ExternalStream, the flag will be false.
-    pub fn is_external_failed(self) -> (Self, bool) {
+    /// Returns `self` and a flag that indicates if the external stream run failed. If `self` is
+    /// not [`PipelineData::ExternalStream`], the flag will be `false`.
+    ///
+    /// Currently this will consume an external stream to completion.
+    pub fn check_external_failed(self) -> (Self, bool) {
         let mut failed_to_run = false;
         // Only need ExternalStream without redirecting output.
         // It indicates we have no more commands to execute currently.