feat(image): make math packages configurable. Closes #1295

lua/snacks/image/doc.lua

@@ -40,7 +40,8 @@ M.transforms = {
     if not content:find("^\\begin") then
       content = ("\\[%s\\]"):format(content)
     end
-    local packages = { "xcolor", "amsmath", "amssymb" }
+    local packages = { "xcolor" }
+    vim.list_extend(packages, Snacks.image.config.convert.math.packages)
     for _, line in ipairs(vim.api.nvim_buf_get_lines(ctx.buf, 0, -1, false)) do
       if line:find("\\usepackage") then
         for _, p in ipairs(vim.split(line:match("{(.-)}") or "", ",%s*")) do

lua/snacks/image/init.lua

@@ -103,6 +103,11 @@ local defaults = {
   ---@class snacks.image.convert.Config
   convert = {
     notify = true, -- show a notification on error
+    math = {
+      -- for latex documents, the doc packages are included automatically,
+      -- but you can add more packages here. Useful for markdown documents.
+      packages = { "amsmath", "amssymb", "amsfonts", "amscd", "mathtools", "physics", "siunitx", "mhchem" },
+    },
     ---@type snacks.image.args
     mermaid = function()
       local theme = vim.o.background == "light" and "neutral" or "dark"