Clarify that truth times are in UTC

src/cogs/auto_responder.py

@@ -184,7 +184,7 @@ class AutoResponder(commands.Cog):
         message: discord.Message,
         *domains: str,
         additional: Iterable[str] = None
-    ) -> discord.File | None:
+    ) -> None:
         additional = additional or []
         links = self.extract_links(message.content, *domains) + list(additional)
         if links:

src/cogs/quote_quota.py

@@ -266,13 +266,16 @@ class QuoteQuota(commands.Cog):
         """
         hrs = [x.zfill(2) for x in hours.keys()]
         plt.clf()
-        plt.title("Truth times")
+        plt.title("Truth times (UTC)")
         plt.xlabel("Hour")
         plt.ylabel("Truths")
         plt.bar(hrs, list(hours.values()), color="#5448EE")
 
+        average = sum(hours.values()) / len(hours)
+        plt.axhline(average, color="red", linestyle="--", label=f"Average: {average:.1f}")
+
         file = io.BytesIO()
-        plt.savefig(file, format="jpg")
+        plt.savefig(file, format="png")
         file.seek(0)
         return discord.File(file, "truths.png")