Syntax highlight expanded code blobs (#12223)
Syntax highlight expanded code blobs (#12223)

Expanded code in diffs wasn't being highlighted properly because it wasn't passing the filename to highlighting code.

Fixes #12218
cez81/gitea,sapk-fork/gitea,sapk-fork/gitea,vCaesar/gitea,cez81/gitea,vdbt/gitea,go-gitea/gitea,sapk-fork/gitea,vdbt/gitea,go-gitea/gitea,cez81/gitea,vCaesar/gitea,go-gitea/gitea,sapk-fork/gitea