style(docs): Change fixed width to adaptive width. (#499)

apps/docs/global.less

@@ -4,11 +4,11 @@
  */
 
 .rspress-doc-container:not(:has(.aside-container_edeb4)) .rspress-doc {
-  width: 1400px;
+  width: auto;
   max-width: 1400px;
 }
 .rspress-doc-container:not(:has(.aside-container_edeb4)) .rspress-doc-footer {
-  width: 1400px;
+  width: auto;
   max-width: 1400px;
 }