Revert "tui: Move ui_bridge module to tui/ namespace."

ui_bridge.c is useful for libnvim consumers, not just the built-in TUI.

This reverts commit beb2e4f095.

src/nvim/tui/tui.c

@@ -22,10 +22,10 @@
 #include "nvim/os/input.h"
 #include "nvim/os/os.h"
 #include "nvim/strings.h"
+#include "nvim/ui_bridge.h"
 #include "nvim/ugrid.h"
 #include "nvim/tui/input.h"
 #include "nvim/tui/tui.h"
-#include "nvim/tui/ui_bridge.h"
 
 // Space reserved in the output buffer to restore the cursor to normal when
 // flushing. No existing terminal will require 32 bytes to do that.

src/nvim/ui_bridge.c

@@ -1,4 +1,5 @@
-// UI wrapper for the built-in TUI. Sends UI requests to the TUI thread.
+// UI wrapper that sends UI requests to the UI thread.
+// Used by the built-in TUI and external libnvim-based UIs.
 
 #include <assert.h>
 #include <stdbool.h>
@@ -9,11 +10,11 @@
 #include "nvim/vim.h"
 #include "nvim/ui.h"
 #include "nvim/memory.h"
+#include "nvim/ui_bridge.h"
 #include "nvim/ugrid.h"
-#include "nvim/tui/ui_bridge.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "tui/ui_bridge.c.generated.h"
+# include "ui_bridge.c.generated.h"
 #endif
 
 #define UI(b) (((UIBridgeData *)b)->ui)

src/nvim/ui_bridge.h

@@ -1,6 +1,7 @@
-// Bridge used for communication between a builtin UI thread and nvim core
-#ifndef NVIM_TUI_UI_BRIDGE_H
-#define NVIM_TUI_UI_BRIDGE_H
+// Bridge for communication between a UI thread and nvim core.
+// Used by the built-in TUI and external libnvim-based UIs.
+#ifndef NVIM_UI_BRIDGE_H
+#define NVIM_UI_BRIDGE_H
 
 #include <uv.h>
 
@@ -39,6 +40,6 @@ struct ui_bridge_data {
 
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "tui/ui_bridge.h.generated.h"
+# include "ui_bridge.h.generated.h"
 #endif
-#endif  // NVIM_TUI_UI_BRIDGE_H
+#endif  // NVIM_UI_BRIDGE_H