git: Add support for using kitty as a difftool

While at it drop unnecessary double quotes.

git/.gitconfig

@@ -3,7 +3,7 @@
 	email = sanchayan@sanchayanmaity.net
 	login = sanchayanmaity
 [core]
-	editor = "nvim"
+	editor = nvim
 	pager = nvim -R
 	excludesfile = ~/.config/git/ignore
 [color]
@@ -18,8 +18,13 @@
 	pruneTags = true
 [diff]
 	tool = nvimdiff
+[difftool]
+	prompt = false
+	trustExitCode = true
 [difftool "nvimdiff"]
-	cmd = nvim -R -d "$LOCAL" "$REMOTE"
+	cmd = nvim -R -d $LOCAL $REMOTE
+[difftool "kitty"]
+    cmd = kitty +kitten diff $LOCAL $REMOTE
 [merge]
 	tool = diffconflicts
 	conflictstyle = diff3
@@ -28,7 +33,7 @@
 	prompt = false
 	keepBackup = false
 [mergetool "diffconflicts"]
-	cmd = nvim -c DiffConflicts "$MERGED" "$BASE" "$LOCAL" "$REMOTE"
+	cmd = nvim -c DiffConflicts $MERGED $BASE $LOCAL $REMOTE
 	trustExitCode = true
 [rebase]
 	autosquash = true