nvim: Use peek for markdown preview where possible

On machines that have deno installed, we use peek instead of
markdown-preview for html-based previews of md files. The preview is
more responsive and in a neater package, as well as just not relying on
any vim plugin stuff to the same degree.
We still fall back to the old markdown-preview if no deno executable is
available.

We also change the key maps slightly to prepare for future 'prose' or
'preview' based mappings: All mappings are registered under the
`<leader>p` layer, with md preview being `<leader>pp` and various
mindmap operations moved to `<leader>pm`.

nvim/.config/nvim/after/ftplugin/markdown.lua

@@ -5,7 +5,7 @@ if require("core.util").is_available("which-key") then
 	require("which-key").register({ ["<localleader>e"] = { name = "+criticmarkup" } })
 end
 
-if require("zk.util").notebook_root(vim.fn.expand("%:p")) ~= nil then
+if require("core.util").is_available("zk") and require("zk.util").notebook_root(vim.fn.expand("%:p")) ~= nil then
 	map("n", "<CR>", "<cmd>lua vim.lsp.buf.definition()<cr>", { silent = true })
 end
 
@@ -22,11 +22,26 @@ map("n", "[c", "?^```<cr>n}:nohl<cr>", { desc = "previous code cell" })
 map("n", "<localleader>co", "o```python<cr><cr>```<esc>k", { desc = "Insert quarto cell below" })
 map("n", "<localleader>cO", "O```python<cr><cr>```<esc>k", { desc = "Insert quarto cell above" })
 
+if require("core.util").is_available("which-key") then
+	require("which-key").register({ ["<localleader>p"] = { name = "+prose" } })
+end
 -- show nice md preview in browser (auto-syncs scrolling)
-map("n", "<localleader>cp", "<Plug>MarkdownPreviewToggle", { desc = "show md preview" })
+if require("core.util").is_available("peek") then
+	local peek = require("peek")
+	local function togglePeek()
+		if peek.is_open() then
+			peek.close()
+		else
+			peek.open()
+		end
+	end
+	map("n", "<leader>pp", togglePeek, { desc = "show md preview" })
+else
+	map("n", "<leader>pp", "<Plug>MarkdownPreviewToggle", { desc = "show md preview" })
+end
 
 -- create mindmaps directly from markdown! requires external executable
 if vim.fn.executable("markmap") then
-	map("n", "<localleader>cm", "<cmd>MarkmapOpen<cr>", { desc = "open md mindmap" })
+	map("n", "<leader>pm", "<cmd>MarkmapOpen<cr>", { desc = "open md mindmap" })
-	map("n", "<localleader>cM", "<cmd>MarkmapWatch<cr>", { desc = "watch for md mindmap" })
+	map("n", "<leader>pM", "<cmd>MarkmapWatch<cr>", { desc = "watch for md mindmap" })
 end

nvim/.config/nvim/lua/plugins/prose.lua

@@ -8,7 +8,7 @@ local prose_plugs = {
 		config = true,
 		cmd = { "ZenMode" },
 		dependencies = { "folke/twilight.nvim" },
-		keys = { { "<leader>sz", ":ZenMode<cr>", { silent = true } } },
+		keys = { { "<leader>sz", ":ZenMode<cr>", silent = true, desc = "toggle zen mode" } },
 	},
 	{
 		"andrewferrier/wrapping.nvim",
@@ -48,8 +48,21 @@ local prose_plugs = {
 		ft = writing_ft,
 	},
 	-- generate an auto-updating html preview for md files
+	-- uses the very nice peek if deno is available, otherwise falls back to markdown-preview
+	{
+		"toppair/peek.nvim",
+		event = { "VeryLazy" },
+		cond = vim.fn.executable("deno") == 1,
+		build = "deno task --quiet build:fast",
+		config = function()
+			require("peek").setup()
+			vim.api.nvim_create_user_command("PeekOpen", require("peek").open, {})
+			vim.api.nvim_create_user_command("PeekClose", require("peek").close, {})
+		end,
+	},
 	{
 		"iamcco/markdown-preview.nvim",
+		cond = vim.fn.executable("deno") == 0,
 		build = function()
 			vim.fn["mkdp#util#install"]()
 		end,