Fix Autocompleter promises

Use bluebird instead of the now removed "q" library.

Also, make sure we timeout and then `reflect` to effectively do an `allSettled` that waits for all promises to either be resolved or rejected. Then we filter for those that are fulfilled and return the completions.

src/autocomplete/Autocompleter.js

@@ -52,21 +52,23 @@ export async function getCompletions(query: string, selection: SelectionRange, f
      otherwise, we run into a condition where new completions are displayed
      while the user is interacting with the list, which makes it difficult
      to predict whether an action will actually do what is intended
-
-     It ends up containing a list of Q promise states, which are objects with
-     state (== "fulfilled" || "rejected") and value. */
-    const completionsList = await Q.allSettled(
-        PROVIDERS.map(provider => {
-            return Promise.resolve(provider.getCompletions(query, selection, force))
-                .timeout(PROVIDER_COMPLETION_TIMEOUT);
-        }),
+    */
+    const completionsList = await Promise.all(
+        // Array of inspections of promises that might timeout. Instead of allowing a
+        // single timeout to reject the Promise.all, reflect each one and once they've all
+        // settled, filter for the fulfilled ones
+        PROVIDERS.map((provider) => {
+            // Convert to bluebird promise so that we can do a timeout
+            const p = Promise.resolve(provider.getCompletions(query, selection, force));
+            return p.timeout(PROVIDER_COMPLETION_TIMEOUT);
+        }).map((p) => p.reflect()),
     );
 
-    return completionsList
-        .filter(completion => completion.state === "fulfilled")
-        .map((completionsState, i) => {
+    return completionsList.filter(
+        (inspection) => inspection.isFulfilled(),
+    ).map((completionsState, i) => {
         return {
-                completions: completionsState.value,
+            completions: completionsState.value(),
             provider: PROVIDERS[i],
 
             /* the currently matched "command" the completer tried to complete