[de] Minor category cleanup: Moved everything that is related to letters and e-mails to one category so it's easier to turn on/off in one go.
[de] Minor category cleanup: Moved everything that is related to letters and e-mails to one category so it's easier to turn on/off in one go.

languagetool-org/languagetool,janissl/languagetool,jimregan/languagetool,janissl/languagetool,jimregan/languagetool,lopescan/languagetool,lopescan/languagetool,languagetool-org/languagetool,jimregan/languagetool,janissl/languagetool,jimregan/languagetool,janissl/languagetool,jimregan/languagetool,lopescan/languagetool,janissl/languagetool,meg0man/languagetool,languagetool-org/languagetool,janissl/languagetool,meg0man/languagetool,lopescan/languagetool,lopescan/languagetool,languagetool-org/languagetool,meg0man/languagetool,meg0man/languagetool,languagetool-org/languagetool,meg0man/languagetool