Apply nightly clippy lints (#9654)

# Description
- A new one is the removal of unnecessary `#` in raw strings without `"`
inside.
-
https://rust-lang.github.io/rust-clippy/master/index.html#/needless_raw_string_hashes
- The automatically applied removal of `.into_iter()` touched several
places where #9648 will change to the use of the record API. If
necessary I can remove them @IanManske to avoid churn with this PR.
- Manually applied `.try_fold` in two places
- Removed a dead `if`
- Manual: Combat rightward-drift with early return

crates/nu-cli/src/commands/keybindings_list.rs

@@ -59,7 +59,7 @@ impl Command for KeybindingsList {
         _input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let records = if call.named_len() == 0 {
-            let all_options = vec!["modifiers", "keycodes", "edits", "modes", "events"];
+            let all_options = ["modifiers", "keycodes", "edits", "modes", "events"];
             all_options
                 .iter()
                 .flat_map(|argument| get_records(argument, &call.head))

crates/nu-cli/src/completions/command_completions.rs

@@ -205,10 +205,7 @@ impl Completer for CommandCompletion {
             vec![]
         };
 
-        subcommands
-            .into_iter()
-            .chain(commands.into_iter())
-            .collect::<Vec<_>>()
+        subcommands.into_iter().chain(commands).collect::<Vec<_>>()
     }
 
     fn get_sort_by(&self) -> SortBy {

crates/nu-cli/src/completions/variable_completions.rs

@@ -294,7 +294,7 @@ fn recursive_value(val: Value, sublevels: Vec<Vec<u8>>) -> Value {
                 vals,
                 span: _,
             } => {
-                for item in cols.into_iter().zip(vals.into_iter()) {
+                for item in cols.into_iter().zip(vals) {
                     // Check if index matches with sublevel
                     if item.0.as_bytes().to_vec() == next_sublevel {
                         // If matches try to fetch recursively the next