Suggest macro import from crate root.

This commit suggests importing a macro from the root of a crate as the
intent may have been to import a macro from the definition location that
was annotated with `#[macro_export]`.

src/test/ui/issue-59764.fixed

@@ -0,0 +1,15 @@
+// aux-build:issue-59764.rs
+// compile-flags:--extern issue_59764
+// edition:2018
+// run-rustfix
+
+use issue_59764::makro;
+//~^ ERROR unresolved import `issue_59764::foo::makro` [E0432]
+
+makro!(bar);
+//~^ ERROR cannot determine resolution for the macro `makro`
+
+fn main() {
+    bar();
+    //~^ ERROR cannot find function `bar` in this scope [E0425]
+}

src/test/ui/issue-59764.rs

@@ -1,6 +1,7 @@
 // aux-build:issue-59764.rs
 // compile-flags:--extern issue_59764
 // edition:2018
+// run-rustfix
 
 use issue_59764::foo::makro;
 //~^ ERROR unresolved import `issue_59764::foo::makro` [E0432]

src/test/ui/issue-59764.stderr

@@ -1,11 +1,17 @@
 error[E0432]: unresolved import `issue_59764::foo::makro`
-  --> $DIR/issue-59764.rs:5:5
+  --> $DIR/issue-59764.rs:6:5
    |
 LL | use issue_59764::foo::makro;
    |     ^^^^^^^^^^^^^^^^^^^^^^^ no `makro` in `foo`
+   |
+   = note: this could be because a macro annotated with `#[macro_export]` will be exported at the root of the crate instead of the module where it is defined
+help: a macro with this name exists at the root of the crate
+   |
+LL | use issue_59764::makro;
+   |     ^^^^^^^^^^^^^^^^^^
 
 error: cannot determine resolution for the macro `makro`
-  --> $DIR/issue-59764.rs:8:1
+  --> $DIR/issue-59764.rs:9:1
    |
 LL | makro!(bar);
    | ^^^^^
@@ -13,7 +19,7 @@ LL | makro!(bar);
    = note: import resolution is stuck, try simplifying macro imports
 
 error[E0425]: cannot find function `bar` in this scope
-  --> $DIR/issue-59764.rs:12:5
+  --> $DIR/issue-59764.rs:13:5
    |
 LL |     bar();
    |     ^^^ not found in this scope