misc(nvim): reload buffer when its file changed on disk

Bump 'updatetime' to 1 second because it affects three things:
- swap file save frequency
- GitGutter signs update frequency
- CursorHold and CursorHoldI trigger frequency
100ms is too high of a frequency.

Enable focus events in tmux for nvim 'FocusGained' event,

Add two event handlers, one for updating the buffer with `checktime`,
another for logging a message when doing so.

3 files changed, 20 insertions, 2 deletions

diff --git a/.config/nvim/init.lua b/.config/nvim/init.lua
index 3f7515c..7ffe81f 100644
--- a/.config/nvim/init.lua
+++ b/.config/nvim/init.lua
@@ -66,6 +66,24 @@ vim.api.nvim_create_autocmd({ "WinEnter", "TermOpen" }, {
 	end,
 })
 
+vim.opt.updatetime = 1000 -- Swap file save frequency; also how often GitGutter signs update in ms
+-- Reload buffer when file has been modified outside of nvim
+vim.api.nvim_create_autocmd({ "FocusGained", "BufEnter", "CursorHold", "CursorHoldI" }, {
+	desc = "Reload buffer when modified outside of nvim",
+	group = vim.g.dotfiles.augroup,
+	pattern = "*",
+	command = "checktime",
+})
+-- Log a message when buffer is reloaded because the file has changed on disk outside of nvim
+vim.api.nvim_create_autocmd({ "FileChangedShellPost" }, {
+	desc = "Notify buffer reloaded because its file has changed on disk",
+	group = vim.g.dotfiles.augroup,
+	pattern = "*",
+	callback = function()
+		vim.notify("File changed on disk, buffer reloaded", vim.log.levels.WARN)
+	end,
+})
+
 ------------------------------------------------------------------------------------------------------------------------
 -- Plugins
 ------------------------------------------------------------------------------------------------------------------------
diff --git a/.config/nvim/plugin/50-git.lua b/.config/nvim/plugin/50-git.lua
index 609ab93..64e6cd0 100644
--- a/.config/nvim/plugin/50-git.lua
+++ b/.config/nvim/plugin/50-git.lua
@@ -4,8 +4,6 @@
 
 vim.pack.add({ "https://github.com/airblade/vim-gitgutter" }) -- Show git status in the gutter
 
-vim.opt.updatetime = 100 -- How often the git signs in the gutter update in ms
-
 vim.keymap.set("n", "<Leader>gt", "<Cmd>GitGutterLineHighlightsToggle<CR>", { desc = "Toggle git line highlighting" })
 vim.keymap.set("n", "<Leader>gg", "<Cmd>GitGutter<CR>", { desc = "Refresh GitGutter" })
 vim.keymap.set("n", "<Leader>gq", "<Cmd>GitGutterQuickFix<CR>", { desc = "Git hunks to quickfix list" })
diff --git a/.config/tmux/tmux.conf b/.config/tmux/tmux.conf
index 3a6be99..434bcf0 100644
--- a/.config/tmux/tmux.conf
+++ b/.config/tmux/tmux.conf
@@ -15,6 +15,8 @@ set-option -g window-status-format              "[#I | #{p18:#{=/18/…:window_n
 set-option -g window-status-current-format      "[ ▶ #I | #{p18:#{=/18/…:window_name}#{?window_flags,#F,}}]"
 set-option -g window-status-current-style "bold"
 
+set-option -g focus-events on
+
 unbind C-b
 set-option -g prefix C-Space
 bind-key C-space send-prefix