fix(markdown): Ignore headings inside code blocks

Fixes #69

lua/symbols-outline/markdown.lua

@@ -1,6 +1,6 @@
 local M = {}
 
----Parses markdown files and returns a table of SymbolInformation[] which is
+-- Parses markdown files and returns a table of SymbolInformation[] which is
 -- used by the plugin to show the outline.
 -- We do this because markdown does not have a LSP.
 -- Note that the headings won't have any hierarchy (as of now).
@@ -9,8 +9,14 @@ function M.handle_markdown()
     local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
     local results = {}
 
+    local is_inside_code_block = false
+
     for line, value in ipairs(lines) do
-        if string.find(value, "^#+ ") then
+        if string.find(value, "^```") then
+            is_inside_code_block = not is_inside_code_block
+        end
+
+        if string.find(value, "^#+ ") and not is_inside_code_block then
             if #results > 0 then
                results[#results].selectionRange["end"].line = line - 1
                results[#results].range["end"].line = line - 1