when adding too much section titles, the toc function is mess up

environment：

hexo: 3.7.1
hexo-cli: 1.1.0
os: Windows_NT 10.0.17134 win32 x64
http_parser: 2.8.0
node: 8.12.0
v8: 6.2.414.66
uv: 1.19.2
zlib: 1.2.11
ares: 1.10.1-DEV
modules: 57
nghttp2: 1.32.0
napi: 3
openssl: 1.0.2p
icu: 60.1
unicode: 10.0
cldr: 32.0
tz: 2017c
chrome: 70.0.3538.67
theme version: lasted commitment 13 May 2018

about 56 section titles ( include h1 to h4) i'm using, when i adding the fiftyth section, these peoblem came out. Any soultuion?

please see the problem article link https://www.silenttwice.com/44.html

tufu9441 / maupassant-hexo

when adding too much section titles, the toc function is mess up #415