cleanup some misc files

.editorconfig

@@ -1,11 +0,0 @@
-root = true
-
-[*]
-indent_style = space
-indent_size = 2
-charset = utf-8
-trim_trailing_whitespace = true
-insert_final_newline = true
-
-[*.md]
-trim_trailing_whitespace = false

.gitattributes

@@ -1 +0,0 @@
-* text=auto

.gitignore

@@ -1,2 +1,2 @@
-result*
-shared/*
+result
+.direnv/

CONTRIBUTING.md

@@ -15,7 +15,7 @@ where you will find a [devshell](https://numtide.github.io/devshell) prompt (whi
 
 There's no formal commit process at this time.
 
-Do try to format the repo before submission, however.
+Do try to format the repo with [treefmt](https://github.com/numtide/treefmt) before submission, however.
 
     nix develop -c treefmt