diff between github and gitlab

gistfile1.txt

$ diff github.txt gitlab.txt 
2c2
< href="#this-is-also----------a-header"
---
> href="#this-is-also-a-header"
5c5
< href="#--lets-try-this-shall-we"
---
> href="#-lets-try-this-shall-we"
8c8
< href="#this-header-has-a-thumbsup-in-it"
---
> href="#this-header-has-a-in-it"
20d19
< href="#-header-7"
24,28d22
< href="#-filter"
< href="#-header-string"
< href="#-ipmap-string-foo"
< href="#-no10"
< href="#-v-and--vv"
31,37c25,31
< href="#--this-is-three"
< href="#---this-is-four"
< href="#this-is----a-five"
< href="#this-is----a-six"
< href="#-this-is----a-seven"
< href="#--this-is----a-eight"
< href="#---this-is----a-nine"
---
> href="#-this-is-three"
> href="#-this-is-four"
> href="#this-is-a-five"
> href="#this-is-a-six"
> href="#-this-is-a-seven"
> href="#-this-is-a-eight"
> href="#-this-is-a-nine"