wezterm: add PastePrimarySelection key assignment

refs: https://github.com/wez/wezterm/issues/183

docs/changelog.markdown

@@ -11,6 +11,8 @@ the feature set may change.  As features stabilize some
 brief notes about them may accumulate here.
 
 * Windows: Fixed AltGr handling for European layouts
+* X11: Added `PastePrimarySelection` key assignment that pastes the contents
+  of the primary selection rather than the clipboard.
 * Removed old TOML config file parsing code
 * Removed old `arg="something"` key binding parameter.  This was a remnant from
   the TOML based configuration.  You're unlikely to notice this unless you

docs/config/keys.markdown

@@ -107,6 +107,7 @@ specified via the `arg` key; see examples below.
 | `SpawnWindow`      | Create a new window |
 | `ToggleFullScreen` | Toggles full screen mode for current window |
 | `Paste`            | Paste the clipboard to the current tab |
+| `PastePrimarySelection`  | X11: Paste the primary selection to the current tab (behaves like `Paste` on other systems).|
 | `ActivateTabRelative` | Activate a tab relative to the current tab.  The `arg` value specifies an offset. eg: `-1` activates the tab to the left of the current tab, while `1` activates the tab to the right. |
 | `ActivateTab` | Activate the tab specified by the `arg` value. eg: `0` activates the leftmost tab, while `1` activates the second tab from the left, and so on. |
 | `IncreaseFontSize` | Increases the font size of the current window by 10% |
@@ -139,6 +140,10 @@ return {
     {key="y", mods="CMD", action=wezterm.action{SpawnCommandInNewWindow={
       args={"top"}
     }}},
+
+    -- If you prefer to paste the primary selection rather than the clipboard
+    -- when running on X11
+    {key="Insert", mods="SHIFT", action="PastePrimarySelection"},
   }
 }
 ```

src/frontend/gui/termwindow.rs

@@ -1344,6 +1344,19 @@ impl TermWindow {
         s
     }
 
+    fn paste_from_clipboard(&mut self, tab: &Rc<dyn Tab>, clipboard: Clipboard) {
+        let tab_id = tab.tab_id();
+        let future = self.window.as_ref().unwrap().get_clipboard(clipboard);
+        promise::spawn::spawn(async move {
+            if let Ok(clip) = future.await {
+                let mux = Mux::get().unwrap();
+                if let Some(tab) = mux.get_tab(tab_id) {
+                    tab.trickle_paste(clip).ok();
+                }
+            }
+        });
+    }
+
     fn perform_key_assignment(
         &mut self,
         tab: &Rc<dyn Tab>,
@@ -1373,20 +1386,10 @@ impl TermWindow {
                     .set_clipboard(self.selection_text(tab));
             }
             Paste => {
-                let tab_id = tab.tab_id();
-                let future = self
-                    .window
-                    .as_ref()
-                    .unwrap()
-                    .get_clipboard(Clipboard::default());
-                promise::spawn::spawn(async move {
-                    if let Ok(clip) = future.await {
-                        let mux = Mux::get().unwrap();
-                        if let Some(tab) = mux.get_tab(tab_id) {
-                            tab.trickle_paste(clip).ok();
+                self.paste_from_clipboard(tab, Clipboard::default());
             }
-                    }
-                });
+            PastePrimarySelection => {
+                self.paste_from_clipboard(tab, Clipboard::PrimarySelection);
             }
             ActivateTabRelative(n) => {
                 self.activate_tab_relative(*n)?;

src/keyassignment.rs

@@ -60,6 +60,7 @@ pub enum KeyAssignment {
     ToggleFullScreen,
     Copy,
     Paste,
+    PastePrimarySelection,
     ActivateTabRelative(isize),
     IncreaseFontSize,
     DecreaseFontSize,