Remove misleading emoji comment

Author: charliermarsh

src/rules/pyupgrade/helpers.rs

@@ -1,11 +1,12 @@
 use once_cell::sync::Lazy;
 use regex::{Captures, Regex};
 
-static CURLY_ESCAPE: Lazy<Regex> = Lazy::new(|| Regex::new(r"(\\N\{[^}]+})|([{}])").unwrap());
+static CURLY_BRACES: Lazy<Regex> = Lazy::new(|| Regex::new(r"(\\N\{[^}]+})|([{}])").unwrap());
 
 pub fn curly_escape(text: &str) -> String {
-    // We don't support emojis right now.
-    CURLY_ESCAPE
+    // Match all curly braces. This will include named unicode escapes (like
+    // \N{SNOWMAN}), which we _don't_ want to escape, so take care to preserve them.
+    CURLY_BRACES
         .replace_all(text, |caps: &Captures| {
             if let Some(match_) = caps.get(1) {
                 match_.as_str().to_string()