Add quotes to hash file autocomplete (#7398)

# Description

Fixes #6741. Autocompleting a dir/file named something like foo#bar will
now complete to \`foo#bar\`

crates/nu-cli/tests/support/completions_helpers.rs

@@ -51,6 +51,45 @@ pub fn new_engine() -> (PathBuf, String, EngineState, Stack) {
     (dir, dir_str, engine_state, stack)
 }
 
+pub fn new_quote_engine() -> (PathBuf, String, EngineState, Stack) {
+    // Target folder inside assets
+    let dir = fs::fixtures().join("quoted_completions");
+    let mut dir_str = dir
+        .clone()
+        .into_os_string()
+        .into_string()
+        .unwrap_or_default();
+    dir_str.push(SEP);
+
+    // Create a new engine with default context
+    let mut engine_state = create_default_context();
+
+    // New stack
+    let mut stack = Stack::new();
+
+    // Add pwd as env var
+    stack.add_env_var(
+        "PWD".to_string(),
+        Value::String {
+            val: dir_str.clone(),
+            span: nu_protocol::Span::new(0, dir_str.len()),
+        },
+    );
+    stack.add_env_var(
+        "TEST".to_string(),
+        Value::String {
+            val: "NUSHELL".to_string(),
+            span: nu_protocol::Span::new(0, dir_str.len()),
+        },
+    );
+
+    // Merge environment into the permanent state
+    let merge_result = engine_state.merge_env(&mut stack, &dir);
+    assert!(merge_result.is_ok());
+
+    (dir, dir_str, engine_state, stack)
+}
+
 // match a list of suggestions with the expected values
 pub fn match_suggestions(expected: Vec<String>, suggestions: Vec<Suggestion>) {
     let expected_len = expected.len();