feat(nvim): add markdown rendering with `render-markdown.nvim`

See https://github.com/MeanderingProgrammer/render-markdown.nvim

- Don't set `'colorcolumn'` and `'conceallevel'` in markdown ftplugin
- Treesitter plugin doesn't install the markdown and markdown_inline
  parsers. `50-markdown.lua` does it instead, so that it is
  self-contained. It also installs extra parsers it needs: yaml, html
  and latex.
- Remove markdown highlight adjustments in `50-colors.lua`
- Remove `markdown/injections.scm` that was disabling treesitter
  highlighting inside fenced code blocks.

3 files changed, 24 insertions, 16 deletions

diff --git a/plugin/10-treesitter.lua b/plugin/10-treesitter.lua
index 4602519..aa68fdc 100644
--- a/plugin/10-treesitter.lua
+++ b/plugin/10-treesitter.lua
@@ -11,8 +11,6 @@ require("nvim-treesitter").install({
 	"ini",
 	"json",
 	"lua",
-	"markdown",
-	"markdown_inline",
 	"readline",
 	"vim",
 	"vimdoc",
diff --git a/plugin/50-colors.lua b/plugin/50-colors.lua
index f713a74..4d9774e 100644
--- a/plugin/50-colors.lua
+++ b/plugin/50-colors.lua
@@ -36,20 +36,6 @@ local function adjust_highlight()
 			vim.api.nvim_set_hl(0, "Cursorline", { bg = "#043624" })
 			vim.api.nvim_set_hl(0, "NormalFloat", { bg = solarized_colors.base02 })
 		end
-
-		-- Markdown highlight
-		if vim.o.background == "light" then
-			vim.api.nvim_set_hl(0, "@markup.raw", { bg = solarized_colors.base2, update = true })
-		elseif vim.o.background == "dark" then
-			vim.api.nvim_set_hl(0, "@markup.raw", { bg = solarized_colors.base02, update = true })
-		end
-		vim.api.nvim_set_hl(0, "@markup.raw.block", { fg = solarized_colors.cyan, update = true })
-		vim.api.nvim_set_hl(0, "@markup.heading.1", { link = "@markup.heading" })
-		vim.api.nvim_set_hl(0, "@markup.heading.2", { link = "@markup.heading" })
-		vim.api.nvim_set_hl(0, "@markup.heading.3", { link = "@markup.heading" })
-		vim.api.nvim_set_hl(0, "@markup.heading.4", { link = "@markup.heading" })
-		vim.api.nvim_set_hl(0, "@markup.heading.5", { link = "@markup.heading" })
-		vim.api.nvim_set_hl(0, "@markup.heading.6", { link = "@markup.heading" })
 	end
 end
 
diff --git a/plugin/50-markdown.lua b/plugin/50-markdown.lua
new file mode 100644
index 0000000..d033d32
--- /dev/null
+++ b/plugin/50-markdown.lua
@@ -0,0 +1,24 @@
+--
+-- Markdown rendering plugin
+--
+-- Uses `render-markdown`, see https://github.com/MeanderingProgrammer/render-markdown.nvim
+
+vim.pack.add({
+	"https://github.com/nvim-treesitter/nvim-treesitter",
+	"https://github.com/nvim-tree/nvim-web-devicons",
+	"https://github.com/MeanderingProgrammer/render-markdown.nvim",
+})
+
+require("nvim-treesitter").install({
+	"html",
+	"latex",
+	"markdown",
+	"markdown_inline",
+	"yaml",
+})
+
+require("render-markdown").setup({
+	heading = { width = "block", min_width = 120 },
+	code = { position = "center", sign = false, width = "block", min_width = 60, left_margin = 2 },
+	dash = { width = 120 },
+})