fish: Add 'trim_trailing_slashes' function and bind it

.config/fish/functions/fish_user_key_bindings.fish

@@ -5,4 +5,5 @@ function fish_user_key_bindings
 	end
 
 	bind \el downcase-word
+	bind \cw trim_trailing_slashes
 end

.config/fish/functions/trim_trailing_slashes.fish

@@ -0,0 +1,10 @@
+# This is useful for rsync when folders have slashes automatically appended to
+# them (e.g. with fzf completion).
+function trim_trailing_slashes --description "Trim trailing slashes of all commandline tokens"
+	set -l list (commandline -o)
+	commandline -r ""
+	for i in $list
+		commandline -i -- (string escape (string replace -r '/$' '' $i))
+		commandline -i -- ' '
+ 	end
+end