meta: Add elementary kitty diff support

Having image diffs in the terminal is very cool, however I ultimately
decided against using kitty's diff feature due to using the existing
colors of the shell being non-trivial.

fish/.config/fish/config.fish

@@ -80,7 +80,9 @@ if not set -q set_abbr
     abbr gcl    "git clone"
     abbr gco    "git checkout"
     abbr gd     "git diff"                  # Show all file changes not staged yet
+    abbr gdi    "git difftool --no-symlinks --dir-diff"
     abbr gds    "git diff --staged"         # Show changes staged but not committed
+    abbr gdsi   "git difftool --no-symlinks --dir-diff --staged"
     abbr gi     "git init"
     abbr gl     "git log --oneline --decorate --all --graph -n 10"
     abbr gm     "git merge"

git/.gitconfig

@@ -12,6 +12,20 @@
     excludesfile = ~/.gitignore
     quotePath = false
 
+[diff]
+  tool = kitty
+  guitool = kitty.gui
+
+[difftool]
+    prompt = false
+    trustExitCode = true
+
+[difftool "kitty"]
+    cmd = kitty +kitten diff $LOCAL $REMOTE
+
+[difftool "kitty.gui"]
+    cmd = kitty kitty +kitten diff $LOCAL $REMOTE
+
 [web]
     browser = qutebrowser
 

kitty/.config/kitty/diff.conf

@@ -0,0 +1,4 @@
+map d scroll_to next-page
+map u scroll_to prev-page
+map g scroll_to start
+map G scroll_to end