Configurable auto-replacements

[MaxEtMoritz]

Is your feature request related to a problem? Please describe.
It would be a good addition to make the auto-replacements configurable, at least to be able to add your own replacements to the list.
Like giuspen already mentioned:

[...] About something configurable may happen too.
#1659 (comment)

Describe the solution you'd like
Some possibility to modify the default auto-replacements. Even a way to just modify it in the settings file directly without UI for it would be enough for me as a starting point.