Consider nicknames when searching for messages (#4663)

Co-authored-by: pajlada <rasmus.karlsson+github@pajlada.com>

src/singletons/Settings.cpp

@@ -81,6 +81,22 @@ bool ConcurrentSettings::isMutedChannel(const QString &channelName)
     return false;
 }
 
+boost::optional<QString> ConcurrentSettings::matchNickname(
+    const QString &usernameText)
+{
+    auto nicknames = getCSettings().nicknames.readOnly();
+
+    for (const auto &nickname : *nicknames)
+    {
+        if (auto nicknameText = nickname.match(usernameText))
+        {
+            return nicknameText;
+        }
+    }
+
+    return boost::none;
+}
+
 void ConcurrentSettings::mute(const QString &channelName)
 {
     mutedChannels.append(channelName);