add tests

Author: rchaser53

tests/source/issue-3851.rs

@@ -0,0 +1,22 @@
+fn main() {
+    let before 
+      // before_comment 
+    = 
+    if true {
+     1.0
+    };
+
+    let after = 
+            // after_comment 
+    if true {
+     1.0
+    };
+
+    let both 
+      // before_comment 
+    = 
+            // after_comment 
+    if true {
+     1.0
+    };
+}

tests/target/issue-3851.rs

@@ -0,0 +1,19 @@
+fn main() {
+    // before_comment
+    let before = if true {
+        1.0
+    };
+
+    let after =
+    // after_comment
+    if true {
+        1.0
+    };
+
+    // before_comment
+    let both =
+    // after_comment
+    if true {
+        1.0
+    };
+}