feat: added peek.nvim, replacing markdown-preview

lua/plugins/peek.lua

+return {
+    "toppair/peek.nvim",
+    event = { "VeryLazy" },
+    build = "deno task --quiet build:fast",
+    config = function()
+        -- default config:
+        require('peek').setup({
+            auto_load = true,        -- whether to automatically load preview when
+            -- entering another markdown buffer
+            close_on_bdelete = true, -- close preview window on buffer delete
+
+            syntax = true,           -- enable syntax highlighting, affects performance
+
+            theme = 'dark',          -- 'dark' or 'light'
+
+            update_on_change = true,
+
+            app = 'browser', -- 'webview', 'browser', string or a table of strings
+            -- explained below
+
+            filetype = { 'markdown' }, -- list of filetypes to recognize as markdown
+
+            -- relevant if update_on_change is true
+            throttle_at = 200000,   -- start throttling when file exceeds this
+            -- amount of bytes in size
+            throttle_time = 'auto', -- minimum amount of time in milliseconds
+            -- that has to pass before starting new render
+        })
+        vim.api.nvim_create_user_command("PeekOpen", require("peek").open, {})
+        vim.api.nvim_create_user_command("PeekClose", require("peek").close, {})
+    end,
+}