Fix collapsible_if false positive with attributes

tests/ui/collapsible_else_if.fixed

@@ -65,4 +65,13 @@ fn main() {
     else {
         println!("!")
     }
+
+    if x == "hello" {
+        print!("Hello ");
+    } else {
+        #[cfg(not(roflol))]
+        if y == "world" {
+            println!("world!")
+        }
+    }
 }

tests/ui/collapsible_else_if.rs

@@ -79,4 +79,13 @@ fn main() {
             println!("!")
         }
     }
+
+    if x == "hello" {
+        print!("Hello ");
+    } else {
+        #[cfg(not(roflol))]
+        if y == "world" {
+            println!("world!")
+        }
+    }
 }

tests/ui/collapsible_if.fixed

@@ -138,4 +138,11 @@ fn main() {
 
     // Fix #5962
     if matches!(true, true) && matches!(true, true) {}
+
+    if true {
+        #[cfg(not(teehee))]
+        if true {
+            println!("Hello world!");
+        }
+    }
 }

tests/ui/collapsible_if.rs

@@ -154,4 +154,11 @@ fn main() {
     if matches!(true, true) {
         if matches!(true, true) {}
     }
+
+    if true {
+        #[cfg(not(teehee))]
+        if true {
+            println!("Hello world!");
+        }
+    }
 }