feat(users/sterni/emacs): set up LanguageTool

Consequently, my emacs config now depends on Java…

Change-Id: I26c63558494fd9a9a7ad5beb4442e50c6a5d89f5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4863
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

users/sterni/emacs/default.nix

@@ -16,6 +16,7 @@ let
     epkgs.melpaPackages.dockerfile-mode
     epkgs.melpaPackages.haskell-mode
     epkgs.melpaPackages.jq-mode
+    epkgs.melpaPackages.languagetool
     epkgs.melpaPackages.markdown-mode
     epkgs.melpaPackages.nix-mode
     epkgs.melpaPackages.sly
@@ -40,8 +41,13 @@ let
         name = "injected-emacs.d";
         destination = "/nix-inject.el";
         text = ''
+          ;; bqn-mode
           (setq bqn-interpreter-path "${pkgs.cbqn}/bin/BQN")
 
+          ;; languagetool
+          (setq languagetool-java-bin "${pkgs.jre}/bin/java")
+          (setq languagetool-language-tool-jar "${pkgs.languagetool}/share/languagetool-commandline.jar")
+
           (provide 'nix-inject)
         '';
       })