feat: add tex tools

lua/plugins/knap.lua

@@ -0,0 +1 @@
+return { "frabjous/knap" }

lua/plugins/vimtex.lua

@@ -0,0 +1,9 @@
+return {
+    "lervag/vimtex",
+    lazy = false, -- we don't want to lazy load VimTeX
+    -- tag = "v2.15", -- uncomment to pin to a specific release
+    init = function()
+        -- VimTeX configuration goes here, e.g.
+        vim.g.vimtex_view_method = "zathura"
+    end
+}