[pre-commit.ci] auto fixes from pre-commit.com hooks

pre-commit-ci[bot] · pre-commit-ci[bot] · commit 92b9aa780794 · 2022-10-17T23:44:27.000Z
for more information, see https://pre-commit.ci
diff --git a/lib/error/404.html b/lib/error/404.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!doctype html>
 <html>
   <head>
     <meta charset="utf-8" />
diff --git a/lib/error/503.html b/lib/error/503.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!doctype html>
 <html>
   <head>
     <meta charset="utf-8" />
diff --git a/lib/error/error.html b/lib/error/error.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!doctype html>
 <html>
   <head>
     <meta charset="utf-8" />
