feat: Support unyank

There are two options to put the unyank ability:
- Option 1: Register a new command like in this CL
- Option 2: Add the unyank to the escape sequence, maybe after the escape_select.

I chose option 1 because the yank function is its own module but the escape
sequence belongs to the tab class. Option 2 is infeasible without touching the
module structure.

I just randomly choose a meaninful and unoccuped key binding for the `unyank`
function. Feel free to modify or remove it from the preset. I personally remap
the yank related functions to dance keys such as ["y" "y"].

yazi-config/preset/keymap.toml

@@ -63,6 +63,7 @@ keymap = [
 	{ on = [ "<Enter>" ],   exec = "open",                                                 desc = "Open the selected files" },
 	{ on = [ "<C-Enter>" ], exec = "open --interactive",                                   desc = "Open the selected files interactively" },
 	{ on = [ "y" ],         exec = [ "yank", "escape --visual --select" ],                 desc = "Copy the selected files" },
+	{ on = [ "Y" ],         exec = [ "unyank", "escape --visual --select" ],               desc = "Remove the files from the yank clipboard" },
 	{ on = [ "x" ],         exec = [ "yank --cut", "escape --visual --select" ],           desc = "Cut the selected files" },
 	{ on = [ "p" ],         exec = "paste",                                                desc = "Paste the files" },
 	{ on = [ "P" ],         exec = "paste --force",                                        desc = "Paste the files (overwrite if the destination exists)" },

yazi-core/src/manager/commands/yank.rs

@@ -18,4 +18,9 @@ impl Manager {
 		self.yanked.1 = self.selected().into_iter().map(|f| f.url()).collect();
 		render!();
 	}
+
+	pub fn unyank(&mut self) -> bool {
+		self.yanked = Default::default();
+		true
+	}
 }