Add ui test for for-loops-over-falibles

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>

Author: xizheyin

tests/ui/lint/for-loops-over-falibles/macro-issue-140747.rs

@@ -0,0 +1,10 @@
+#![forbid(for_loops_over_fallibles)]
+
+fn main() {
+    macro_rules! x {
+        () => {
+            None::<i32> //~ ERROR for loop over an `Option`. This is more readably written as an `if let` statement [for_loops_over_fallibles]
+        };
+    }
+    for _ in x! {} {}
+}

tests/ui/lint/for-loops-over-falibles/macro-issue-140747.stderr

@@ -0,0 +1,32 @@
+error: for loop over an `Option`. This is more readably written as an `if let` statement
+  --> $DIR/macro-issue-140747.rs:6:13
+   |
+LL |             None::<i32>
+   |             ^^^^^^^^^^^
+...
+LL |     for _ in x! {} {}
+   |              ----- in this macro invocation
+   |
+note: the lint level is defined here
+  --> $DIR/macro-issue-140747.rs:1:11
+   |
+LL | #![forbid(for_loops_over_fallibles)]
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in the macro `x` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: to check pattern in a loop use `while let`
+   |
+LL ~             ) =
+LL |         };
+LL |     }
+LL ~     while let Some(_ in x! {} {}
+   |
+help: consider using `if let` to clear intent
+   |
+LL ~             ) =
+LL |         };
+LL |     }
+LL ~     if let Some(_ in x! {} {}
+   |
+
+error: aborting due to 1 previous error
+