add a notification on success

[jemand771]

if your latex document has no warnings, the container output can be somewhat confusing:

main.pdf doesn't exist, not generating diff!

as a vscode task:

Executing task: docker run <...> ghcr.io/jemand771/latex-build

main.pdf doesn't exist, not generating diff!

Terminal will be reused by tasks, press any key to close it.

While this doesnt explicitly state that something went wrong, the lack of positive feedback suggests that the build might have failed. To counter this, a "success" message shall be added. e.g.:

build successful! files written: main.pdf, main-diff.pdf, main.synctex

[DSczyrba]

Dauert irgendwie ganzschön lang :D @jemand771

[jemand771]

stress mich nicht xD