feat(plugins): add markdown edit visual-mode formatting bindings

lua/plugins/markdown-edit.lua

@@ -0,0 +1,27 @@
+--- `<Leader>e` visual-mode formatting binds for markdown/mdx buffers; the
+--- editing itself lives in config.markdown_edit.
+---
+--- Buffer-local so `<Leader>e` stays the git files picker everywhere else.
+--- @module plugins.markdown-edit
+
+---@type LazySpec
+return {
+  "AstroNvim/astrocore",
+  ---@type AstroCoreOpts
+  opts = {
+    autocmds = {
+      markdown_edit = {
+        {
+          event = "FileType",
+          -- `markdown.*` catches the `markdown.mdx` buffers the mdx pack sets
+          -- up; a plain `markdown` pattern does not match a dotted filetype
+          pattern = { "markdown", "markdown.*" },
+          desc = "Markdown formatting binds for the visual selection",
+          callback = function(args)
+            require("astrocore").set_mappings(require("config.markdown_edit").mappings, { buffer = args.buf })
+          end,
+        },
+      },
+    },
+  },
+}