Path migration part 3: $nu paths (#13368)

# Description
Part 3 of replacing `std::path` types with `nu_path` types added in
#13115. This PR targets the paths listed in `$nu`. That is, the home,
config, data, and cache directories.

src/config_files.rs

@@ -121,7 +121,7 @@ pub(crate) fn read_config_file(
             }
         }
 
-        eval_config_contents(config_path, engine_state, stack);
+        eval_config_contents(config_path.into(), engine_state, stack);
     }
 }
 
@@ -141,7 +141,7 @@ pub(crate) fn read_loginshell_file(engine_state: &mut EngineState, stack: &mut S
         warn!("loginshell_file: {}", config_path.display());
 
         if config_path.exists() {
-            eval_config_contents(config_path, engine_state, stack);
+            eval_config_contents(config_path.into(), engine_state, stack);
         }
     }
 }
@@ -302,7 +302,7 @@ pub(crate) fn set_config_path(
         Some(s) => canonicalize_with(&s.item, cwd).ok(),
         None => nu_path::config_dir().map(|mut p| {
             p.push(NUSHELL_FOLDER);
-            let mut p = canonicalize_with(&p, cwd).unwrap_or(p);
+            let mut p = canonicalize_with(&p, cwd).unwrap_or(p.into());
             p.push(default_config_name);
             canonicalize_with(&p, cwd).unwrap_or(p)
         }),

src/main.rs

@@ -79,7 +79,7 @@ fn main() -> Result<()> {
     // there is an error reading it, these values will be used.
     let nushell_config_path = if let Some(mut path) = nu_path::config_dir() {
         path.push("nushell");
-        path
+        path.into()
     } else {
         // Not really sure what to default this to if nu_path::config_dir() returns None
         std::path::PathBuf::new()
@@ -99,8 +99,9 @@ fn main() -> Result<()> {
                         default: nushell_config_path.display().to_string(),
                     },
                 );
-            } else if let Some(old_config) =
-                nu_path::get_canonicalized_path(dirs::config_dir()).map(|p| p.join("nushell"))
+            } else if let Some(old_config) = dirs::config_dir()
+                .and_then(|p| p.canonicalize().ok())
+                .map(|p| p.join("nushell"))
             {
                 let xdg_config_empty = nushell_config_path
                     .read_dir()
@@ -125,7 +126,7 @@ fn main() -> Result<()> {
     let default_nushell_completions_path = if let Some(mut path) = nu_path::data_dir() {
         path.push("nushell");
         path.push("completions");
-        path
+        path.into()
     } else {
         std::path::PathBuf::new()
     };
@@ -220,7 +221,7 @@ fn main() -> Result<()> {
     start_time = std::time::Instant::now();
     set_config_path(
         &mut engine_state,
-        &init_cwd,
+        init_cwd.as_ref(),
         "config.nu",
         "config-path",
         parsed_nu_cli_args.config_file.as_ref(),
@@ -228,7 +229,7 @@ fn main() -> Result<()> {
 
     set_config_path(
         &mut engine_state,
-        &init_cwd,
+        init_cwd.as_ref(),
         "env.nu",
         "env-path",
         parsed_nu_cli_args.env_file.as_ref(),
@@ -257,7 +258,7 @@ fn main() -> Result<()> {
 
     start_time = std::time::Instant::now();
     // First, set up env vars as strings only
-    gather_parent_env_vars(&mut engine_state, &init_cwd);
+    gather_parent_env_vars(&mut engine_state, init_cwd.as_ref());
     perf!("gather env vars", start_time, use_color);
 
     engine_state.add_env_var(