Force FilterBar to update auto-complete suggestions after a completion

In the filters for the network and console, there are an initial
set of possible autocompletions for different filter types such as
"method, mime-type, domain, etc". After using tab to autocomplete one
of these suggestions, a different set of autocompletion options should
appear, i.e. "method:GET, method:POST, etc"

However, the TextPrompt object does not currently update the
completion list after accepting an initial completion.

This PR causes the TextPrompt to fetch autocompletion suggestions
after accepting an initial autocomplete to account for these
cases.

Before: https://imgur.com/QiLXkKD
After: https://imgur.com/taEUUw3

Bug: 1138624
Change-Id: Ib5aca39967672b22de97285dd8c5df238a6eafa4
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2472845
Reviewed-by: Robert Paveza <Rob.Paveza@microsoft.com>
Commit-Queue: Brandon Goddard <brgoddar@microsoft.com>

front_end/ui/TextPrompt.js

@@ -446,7 +446,9 @@ export class TextPrompt extends Common.ObjectWrapper.ObjectWrapper {
     if (!result) {
       result = this._acceptSuggestionInternal();
     }
-
+    if (result) {
+      this.autoCompleteSoon();
+    }
     return result;
   }