Merge #1821

1821: Macro completion tweaks r=matklad a=SomeoneToIgnore

Thanks @uHOOCCOOHu for making the macro completion happen :)

I've added a few tweaks to the current completion to make it a bit more convenient:

* Automatically add braces and put the editor cursor inside of them:
<img width="159" alt="image" src="https://user-images.githubusercontent.com/2690773/64737220-022b9f00-d4f5-11e9-8088-76d4678921ab.png">

Currently I have to add the braces manually which is a bit cumbersome.
One further improvement can be to detect if macro accepts no parameters and place the cursor differently for this case.

* Add an exclamation mark to the macro completion label

This helps to distinguish macros from other completion items and also allows to show only macros in completion if you type `!`:
<img width="722" alt="image" src="https://user-images.githubusercontent.com/2690773/64736987-8b8ea180-d4f4-11e9-8355-2ce4f83b7aa8.png">

<img width="732" alt="image" src="https://user-images.githubusercontent.com/2690773/64737214-ffc94500-d4f4-11e9-946e-1ba2db1c7fb1.png">


Additionally, automatic formatting hooks had adjusted two `help.rs` files, I've added them as a last commit to the PR even though they are not really related.

Co-authored-by: Kirill Bulatov <[email protected]>

1 files changed, 30 insertions, 2 deletions

diff --git a/crates/ra_ide_api/src/completion/complete_macro_in_item_position.rs b/crates/ra_ide_api/src/completion/complete_macro_in_item_position.rs
index 708dc9777..6fcef4a72 100644
--- a/crates/ra_ide_api/src/completion/complete_macro_in_item_position.rs
+++ b/crates/ra_ide_api/src/completion/complete_macro_in_item_position.rs
@@ -37,14 +37,42 @@ mod tests {
             ),
             @r##"[
     CompletionItem {
-        label: "foo",
+        label: "foo!",
         source_range: [46; 46),
         delete: [46; 46),
-        insert: "foo!",
+        insert: "foo!($0)",
         kind: Macro,
         detail: "macro_rules! foo",
     },
 ]"##
         );
     }
+
+    #[test]
+    fn completes_vec_macros_with_square_brackets() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                "
+                //- /main.rs
+                macro_rules! vec {
+                    () => {}
+                }
+
+                fn foo() {}
+
+                <|>
+                "
+            ),
+            @r##"[
+    CompletionItem {
+        label: "vec!",
+        source_range: [46; 46),
+        delete: [46; 46),
+        insert: "vec![$0]",
+        kind: Macro,
+        detail: "macro_rules! vec",
+    },
+]"##
+        );
+    }
 }