Generalize logic pointing at binding moved into closure

Account not only for `fn` parameters when moving non-`Copy` values into closure, but also for let bindings.

```
error[E0507]: cannot move out of `bar`, a captured variable in an `FnMut` closure
  --> $DIR/borrowck-move-by-capture.rs:9:29
   |
LL |     let bar: Box<_> = Box::new(3);
   |         ---  ------ move occurs because `bar` has type `Box<isize>`, which does not implement the `Copy` trait
   |         |
   |         captured outer variable
LL |     let _g = to_fn_mut(|| {
   |                        -- captured by this `FnMut` closure
LL |         let _h = to_fn_once(move || -> isize { *bar });
   |                             ^^^^^^^^^^^^^^^^   ---- variable moved due to use in closure
   |                             |
   |                             `bar` is moved here
   |
help: consider cloning the value before moving it into the closure
   |
LL ~         let value = bar.clone();
LL ~         let _h = to_fn_once(move || -> isize { value });
   |
```

```
error[E0507]: cannot move out of `y`, a captured variable in an `Fn` closure
  --> $DIR/unboxed-closures-move-upvar-from-non-once-ref-closure.rs:12:9
   |
LL |     let y = vec![format!("World")];
   |         -   ---------------------- move occurs because `y` has type `Vec<String>`, which does not implement the `Copy` trait
   |         |
   |         captured outer variable
LL |     call(|| {
   |          -- captured by this `Fn` closure
LL |         y.into_iter();
   |         ^ ----------- `y` moved due to this method call
   |         |
   |         `y` is moved here
   |
note: `into_iter` takes ownership of the receiver `self`, which moves `y`
  --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
help: you can `clone` the value and consume it, but this might not be your desired behavior
   |
LL |         <Vec<String> as Clone>::clone(&y).into_iter();
   |         +++++++++++++++++++++++++++++++ +
help: consider cloning the value if the performance cost is acceptable
   |
LL |         y.clone().into_iter();
   |          ++++++++
```

2 files changed, 16 insertions, 20 deletions

diff --git a/tests/ui/suggestions/option-content-move2.stderr b/tests/ui/suggestions/option-content-move2.stderr
index be97cba17b9..436441d6f1b 100644
--- a/tests/ui/suggestions/option-content-move2.stderr
+++ b/tests/ui/suggestions/option-content-move2.stderr
@@ -2,7 +2,9 @@ error[E0507]: cannot move out of `var`, a captured variable in an `FnMut` closur
   --> $DIR/option-content-move2.rs:11:9
    |
 LL |     let mut var = None;
-   |         ------- captured outer variable
+   |         -------   ---- move occurs because `var` has type `Option<NotCopyable>`, which does not implement the `Copy` trait
+   |         |
+   |         captured outer variable
 LL |     func(|| {
    |          -- captured by this `FnMut` closure
 LL |         // Shouldn't suggest `move ||.as_ref()` here
@@ -10,16 +12,15 @@ LL |         move || {
    |         ^^^^^^^ `var` is moved here
 LL |
 LL |             var = Some(NotCopyable);
-   |             ---
-   |             |
-   |             variable moved due to use in closure
-   |             move occurs because `var` has type `Option<NotCopyable>`, which does not implement the `Copy` trait
+   |             --- variable moved due to use in closure
 
 error[E0507]: cannot move out of `var`, a captured variable in an `FnMut` closure
   --> $DIR/option-content-move2.rs:21:9
    |
 LL |     let mut var = None;
-   |         ------- captured outer variable
+   |         -------   ---- move occurs because `var` has type `Option<NotCopyableButCloneable>`, which does not implement the `Copy` trait
+   |         |
+   |         captured outer variable
 LL |     func(|| {
    |          -- captured by this `FnMut` closure
 LL |         // Shouldn't suggest `move ||.as_ref()` nor to `clone()` here
@@ -27,10 +28,7 @@ LL |         move || {
    |         ^^^^^^^ `var` is moved here
 LL |
 LL |             var = Some(NotCopyableButCloneable);
-   |             ---
-   |             |
-   |             variable moved due to use in closure
-   |             move occurs because `var` has type `Option<NotCopyableButCloneable>`, which does not implement the `Copy` trait
+   |             --- variable moved due to use in closure
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/suggestions/option-content-move3.stderr b/tests/ui/suggestions/option-content-move3.stderr
index faaf8a9df9d..68c52352a65 100644
--- a/tests/ui/suggestions/option-content-move3.stderr
+++ b/tests/ui/suggestions/option-content-move3.stderr
@@ -26,17 +26,16 @@ error[E0507]: cannot move out of `var`, a captured variable in an `FnMut` closur
   --> $DIR/option-content-move3.rs:12:9
    |
 LL |     let var = NotCopyable;
-   |         --- captured outer variable
+   |         ---   ----------- move occurs because `var` has type `NotCopyable`, which does not implement the `Copy` trait
+   |         |
+   |         captured outer variable
 LL |     func(|| {
    |          -- captured by this `FnMut` closure
 LL |         // Shouldn't suggest `move ||.as_ref()` here
 LL |         move || {
    |         ^^^^^^^ `var` is moved here
 LL |             let x = var;
-   |                     ---
-   |                     |
-   |                     variable moved due to use in closure
-   |                     move occurs because `var` has type `NotCopyable`, which does not implement the `Copy` trait
+   |                     --- variable moved due to use in closure
    |
 note: if `NotCopyable` implemented `Clone`, you could clone the value
   --> $DIR/option-content-move3.rs:2:1
@@ -67,17 +66,16 @@ error[E0507]: cannot move out of `var`, a captured variable in an `FnMut` closur
   --> $DIR/option-content-move3.rs:23:9
    |
 LL |     let var = NotCopyableButCloneable;
-   |         --- captured outer variable
+   |         ---   ----------------------- move occurs because `var` has type `NotCopyableButCloneable`, which does not implement the `Copy` trait
+   |         |
+   |         captured outer variable
 LL |     func(|| {
    |          -- captured by this `FnMut` closure
 LL |         // Shouldn't suggest `move ||.as_ref()` here
 LL |         move || {
    |         ^^^^^^^ `var` is moved here
 LL |             let x = var;
-   |                     ---
-   |                     |
-   |                     variable moved due to use in closure
-   |                     move occurs because `var` has type `NotCopyableButCloneable`, which does not implement the `Copy` trait
+   |                     --- variable moved due to use in closure
    |
 help: consider cloning the value before moving it into the closure
    |