Improve Find/Replace shortcuts (#10297)

This PR changes ways the Find/Replace functionality in the
Buffer/Project Search is accessible via shortcuts. It makes those panels
work the same way as in VS Code and Sublime Text.

The details are described in the issue: [Make Find/Replace easier to
use](https://github.com/zed-industries/zed/issues/9142)

There's a difficulty with the Linux keybindings:

VS Code uses on MacOS (this PR replicates it):

| Action | Buffer Search | Project Search |
| --- | --- | --- |
| Find | `cmd-f` | `cmd-shift-f` |
| Replace | `cmd-alt-f` | `cmd-shift-h` |

VS Code uses on Linux (this PR replicates all but one):

| Action | Buffer Search | Project Search |
| --- | --- | --- |
| Find | `ctrl-f` | `ctrl-shift-f` |
| Replace | `ctrl-h` ❗ | `ctrl-shift-h` |

The problem is that `ctrl-h` is already taken by the `editor::Backspace`
action in Zed on Linux.

There's two options here:

1. Change keybinding for `editor::Backspace` on Linux to something else,
and use `ctrl-h` for the "replace in buffer" action.
2. Use some other keybinding on Linux in Zed. This PR introduces
`ctrl-r` for this purpose, though I'm not sure it's the best choice.

What do you think?

fixes #9142

Release Notes:

- Improved access to "Find/Replace in Buffer" and "Find/Replace in
Files" via shortcuts (#9142).

Optionally, include screenshots / media showcasing your addition that
can be included in the release notes.

- N/A

assets/keymaps/default-linux.json

@@ -28,7 +28,7 @@
       "ctrl-0": "zed::ResetBufferFontSize",
       "ctrl-,": "zed::OpenSettings",
       "ctrl-q": "zed::Quit",
-      "ctrl-h": "zed::Hide",
+      "alt-f9": "zed::Hide",
       "f11": "zed::ToggleFullScreen"
     }
   },
@@ -38,7 +38,6 @@
       "escape": "editor::Cancel",
       "backspace": "editor::Backspace",
       "shift-backspace": "editor::Backspace",
-      "ctrl-h": "editor::Backspace",
       "delete": "editor::Delete",
       "ctrl-d": "editor::Delete",
       "tab": "editor::Tab",
@@ -150,10 +149,11 @@
       "ctrl-shift-enter": "editor::NewlineBelow",
       "ctrl-enter": "editor::NewlineAbove",
       "alt-z": "editor::ToggleSoftWrap",
-      "ctrl-f": [
+      "ctrl-f": "buffer_search::Deploy",
+      "ctrl-h": [
         "buffer_search::Deploy",
         {
-          "focus": true
+          "replace_enabled": true
         }
       ],
       // "cmd-e": [
@@ -212,7 +212,9 @@
       "enter": "search::SelectNextMatch",
       "shift-enter": "search::SelectPrevMatch",
       "alt-enter": "search::SelectAllMatches",
-      "alt-tab": "search::CycleMode"
+      "alt-tab": "search::CycleMode",
+      "ctrl-f": "search::FocusSearch",
+      "ctrl-h": "search::ToggleReplace"
     }
   },
   {
@@ -234,6 +236,7 @@
     "bindings": {
       "escape": "project_search::ToggleFocus",
       "alt-tab": "search::CycleMode",
+      "ctrl-shift-f": "search::FocusSearch",
       "ctrl-shift-h": "search::ToggleReplace",
       "alt-ctrl-g": "search::ActivateRegexMode",
       "alt-ctrl-x": "search::ActivateTextMode"
@@ -419,6 +422,12 @@
       "ctrl-j": "workspace::ToggleBottomDock",
       "ctrl-alt-y": "workspace::CloseAllDocks",
       "ctrl-shift-f": "pane::DeploySearch",
+      "ctrl-shift-h": [
+        "pane::DeploySearch",
+        {
+          "replace_enabled": true
+        }
+      ],
       "ctrl-k ctrl-s": "zed::OpenKeymap",
       "ctrl-k ctrl-t": "theme_selector::Toggle",
       "ctrl-shift-t": "project_symbols::Toggle",