Fix Helix mode search & selection (#42928)

This PR redoes the desired behavior changes of #41583 (reverted in
#42892) but less invasively

Closes #41125
Closes #41164

Release Notes:

- N/A

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

assets/keymaps/vim.json

@@ -421,6 +421,12 @@
       "ctrl-[": "editor::Cancel"
     }
   },
+  {
+    "context": "vim_mode == helix_select && !menu",
+    "bindings": {
+      "escape": "vim::SwitchToHelixNormalMode"
+    }
+  },
   {
     "context": "(vim_mode == helix_normal || vim_mode == helix_select) && !menu",
     "bindings": {
@@ -470,6 +476,9 @@
       "alt-p": "editor::SelectPreviousSyntaxNode",
       "alt-n": "editor::SelectNextSyntaxNode",
 
+      "n": "vim::HelixSelectNext",
+      "shift-n": "vim::HelixSelectPrevious",
+
       // Goto mode
       "g e": "vim::EndOfDocument",
       "g h": "vim::StartOfLine",