Match hashtags suggestions with regex as well

In previous change 428377 we missed to handle the case
where the input is a regex. This will fix that.

Solves: bug 344608194
Release-Notes: skip
Change-Id: I8f1588c09459c76e888b22b7f992b9a8f0064c99
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
index 7d35629..b008bcc 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
@@ -1149,6 +1149,7 @@
   private getHashtagSuggestions(
     input: string
   ): Promise<AutocompleteSuggestion[]> {
+    const inputReg = input.startsWith('^') ? new RegExp(input) : null;
     return this.restApiService
       .getChangesWithSimilarHashtag(input, throwingErrorCallback)
       .then(response =>
@@ -1156,7 +1157,9 @@
           .flatMap(change => change.hashtags ?? [])
           .filter(isDefined)
           .filter(unique)
-          .filter(hashtag => hashtag.includes(input))
+          .filter(hashtag =>
+            inputReg ? inputReg.test(hashtag) : hashtag.includes(input)
+          )
           .map(hashtag => {
             return {name: hashtag, value: hashtag};
           })