fix(sidebar): fix sidebar when you open a nested link (#73)

Author: pikax

Diff for: src/client/theme-default/components/SideBar.ts

@@ -136,7 +136,8 @@ function resolveMultiSidebar(
   headers: Header[],
   depth: number
 ): ResolvedSidebar {
-  const item = config[getPathDirName(path)]
+  const paths = [path, Object.keys(config)[0]]
+  const item = paths.map((x) => config[getPathDirName(x)]).find(Boolean)
 
   if (Array.isArray(item)) {
     return resolveArraySidebar(item, depth)