Cut down unnecessary lint allows (#14335)

Trying to reduce lint allows either by checking if they are former false
positives or by fixing the underlying warning.

- **Remove dead `allow(dead_code)`**
- **Remove recursive dead code**
- **Remove dead code**
- **Move test only functions to test module**
  The unit tests that use them, themselves are somewhat sus in that they
mock the usage and not test specificly used methods of the
implementation, so there is a risk for divergence
- **Remove `clippy::uninit_vec` allow.**
  May have been a false positive, or the impl has changed somewhat.
We certainly want to look at the unsafe code here to vet for
correctness.

crates/nu-cli/src/prompt_update.rs

@@ -30,30 +30,21 @@ pub(crate) const TRANSIENT_PROMPT_MULTILINE_INDICATOR: &str =
 pub(crate) const PRE_PROMPT_MARKER: &str = "\x1b]133;A\x1b\\";
 pub(crate) const POST_PROMPT_MARKER: &str = "\x1b]133;B\x1b\\";
 pub(crate) const PRE_EXECUTION_MARKER: &str = "\x1b]133;C\x1b\\";
-#[allow(dead_code)]
 pub(crate) const POST_EXECUTION_MARKER_PREFIX: &str = "\x1b]133;D;";
-#[allow(dead_code)]
 pub(crate) const POST_EXECUTION_MARKER_SUFFIX: &str = "\x1b\\";
 
 // OSC633 is the same as OSC133 but specifically for VSCode
 pub(crate) const VSCODE_PRE_PROMPT_MARKER: &str = "\x1b]633;A\x1b\\";
 pub(crate) const VSCODE_POST_PROMPT_MARKER: &str = "\x1b]633;B\x1b\\";
-#[allow(dead_code)]
 pub(crate) const VSCODE_PRE_EXECUTION_MARKER: &str = "\x1b]633;C\x1b\\";
-#[allow(dead_code)]
 //"\x1b]633;D;{}\x1b\\"
 pub(crate) const VSCODE_POST_EXECUTION_MARKER_PREFIX: &str = "\x1b]633;D;";
-#[allow(dead_code)]
 pub(crate) const VSCODE_POST_EXECUTION_MARKER_SUFFIX: &str = "\x1b\\";
-#[allow(dead_code)]
 //"\x1b]633;E;{}\x1b\\"
 pub(crate) const VSCODE_COMMANDLINE_MARKER_PREFIX: &str = "\x1b]633;E;";
-#[allow(dead_code)]
 pub(crate) const VSCODE_COMMANDLINE_MARKER_SUFFIX: &str = "\x1b\\";
-#[allow(dead_code)]
 // "\x1b]633;P;Cwd={}\x1b\\"
 pub(crate) const VSCODE_CWD_PROPERTY_MARKER_PREFIX: &str = "\x1b]633;P;Cwd=";
-#[allow(dead_code)]
 pub(crate) const VSCODE_CWD_PROPERTY_MARKER_SUFFIX: &str = "\x1b\\";
 
 pub(crate) const RESET_APPLICATION_MODE: &str = "\x1b[?1l";

crates/nu-cli/src/reedline_config.rs

@@ -711,7 +711,6 @@ pub(crate) fn create_keybindings(config: &Config) -> Result<KeybindingsMode, She
     }
     for keybinding in parsed_keybindings {
         add_keybinding(
-            &keybinding.name,
             &keybinding.mode,
             keybinding,
             config,
@@ -730,9 +729,7 @@ pub(crate) fn create_keybindings(config: &Config) -> Result<KeybindingsMode, She
     }
 }
 
-#[allow(clippy::only_used_in_recursion)]
 fn add_keybinding(
-    name: &Option<Value>,
     mode: &Value,
     keybinding: &ParsedKeybinding,
     config: &Config,
@@ -755,7 +752,6 @@ fn add_keybinding(
         Value::List { vals, .. } => {
             for inner_mode in vals {
                 add_keybinding(
-                    name,
                     inner_mode,
                     keybinding,
                     config,