feat(plugins): render-markdown.nvim support

squashme!
sqaushme!

lua/astrotheme/groups/plugins/init.lua

@@ -28,6 +28,7 @@ return {
   ["nvim-web-devicons"] = "nvim-web-devicons",
   ["nvim-window-picker"] = "nvim-window-picker",
   ["rainbow-delimiters.nvim"] = "rainbow-delimiters",
+  ["render-markdown.nvim"] = "render-markdown",
   ["spotlight.nvim"] = "spotlight",
   ["symbols-outline.nvim"] = "symbols-outline",
   ["telescope.nvim"] = "telescope",

lua/astrotheme/groups/plugins/render-markdown.lua

@@ -0,0 +1,53 @@
+---@type AstroThemeCallback
+local function callback(c)
+  local color = require "astrotheme.lib.color"
+
+  return {
+    RenderMarkdownH1 = { link = "@markup.heading.1.markdown" },
+    RenderMarkdownH2 = { link = "@markup.heading.2.markdown" },
+    RenderMarkdownH3 = { link = "@markup.heading.3.markdown" },
+    RenderMarkdownH4 = { link = "@markup.heading.4.markdown" },
+    RenderMarkdownH5 = { link = "@markup.heading.5.markdown" },
+    RenderMarkdownH6 = { link = "@markup.heading.6.markdown" },
+
+    RenderMarkdownH1Bg = {
+      fg = c.syntax.purple,
+      bg = color.new(c.syntax.purple):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+    RenderMarkdownH2Bg = {
+      fg = c.syntax.blue,
+      bg = color.new(c.syntax.blue):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+    RenderMarkdownH3Bg = {
+      fg = c.syntax.cyan,
+      bg = color.new(c.syntax.cyan):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+    RenderMarkdownH4Bg = {
+      fg = c.syntax.green,
+      bg = color.new(c.syntax.green):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+    RenderMarkdownH5Bg = {
+      fg = c.syntax.yellow,
+      bg = color.new(c.syntax.yellow):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+    RenderMarkdownH6Bg = {
+      fg = c.syntax.purple,
+      bg = color.new(c.syntax.yellow):blend(color.new(c.ui.base), 0.75):tohex(),
+      bold = true,
+    },
+
+    RenderMarkdownCode = { bg = c.ui.tool },
+    RenderMarkDownBullet = { link = "@markup.list.markdown" },
+    RenderMarkdownChecked = { link = "@markup.list.checked" },
+    RenderMarkdownUnchecked = { link = "@markup.list.unchecked" },
+    RenderMarkdownTodo = { fg = c.ui.green, bold = true },
+    RenderMarkDownLink = { fg = c.ui.blue, bold = true },
+  }
+end
+
+return callback