Fix too_many_lines false positive

Fixes #4364

Author: Michael Wright

clippy_lints/src/functions.rs

@@ -200,7 +200,7 @@ impl<'a, 'tcx> Functions {
             Some(i) => i + 1,
             None => 0,
         };
-        let end_brace_idx = match code_snippet.find('}') {
+        let end_brace_idx = match code_snippet.rfind('}') {
             Some(i) => i,
             None => code_snippet.len(),
         };

tests/ui/functions_maxlines.rs

@@ -56,6 +56,7 @@ fn good_lines() {
 }
 
 fn bad_lines() {
+    println!("Dont get confused by braces: {{}}");
     println!("This is bad.");
     println!("This is bad.");
     println!("This is bad.");

tests/ui/functions_maxlines.stderr

@@ -2,7 +2,7 @@ error: This function has a large number of lines.
   --> $DIR/functions_maxlines.rs:58:1
    |
 LL | / fn bad_lines() {
-LL | |     println!("This is bad.");
+LL | |     println!("Dont get confused by braces: {{}}");
 LL | |     println!("This is bad.");
 LL | |     println!("This is bad.");
 ...  |