fix: handle leading spaces in checkbox bullet

## Details

Issue: #158

This is similar to the already solved issue of leading space in the
first list item of "overly" indented lists. I say overly because
technically the markdown syntax is specific to 2 spaces per indentation
level for lists.

To resolve this rather than concealing the entire list marker range only
conceal the range after any leading white space.

I'm not entirely sure why concealing the full range causes some text to
be cut off for me. I'm guessing there is some strangeness in what it
means to conceal empty space but that is a guess on my part. Adjusting
the range seems to work well in either case.

Author: MeanderingProgrammer

lua/render-markdown/handler/markdown.lua

@@ -116,9 +116,15 @@ function Handler:list_marker(info)
         end
         return false
     end
+
+    -- List markers from tree-sitter should have leading spaces removed, however there are known
+    -- edge cases in the parser: https://github.com/tree-sitter-grammars/tree-sitter-markdown/issues/127
+    -- As a result we account for leading spaces here, can remove if this gets fixed upstream
+    local leading_spaces = str.leading_spaces(info.text)
+
     if sibling_checkbox() then
         -- Hide the list marker for checkboxes rather than replacing with a bullet point
-        self.marks:add(true, info.start_row, info.start_col, {
+        self.marks:add(true, info.start_row, info.start_col + leading_spaces, {
             end_row = info.end_row,
             end_col = info.end_col,
             conceal = '',
@@ -133,10 +139,6 @@ function Handler:list_marker(info)
         if icon == nil then
             return
         end
-        -- List markers from tree-sitter should have leading spaces removed, however there are known
-        -- edge cases in the parser: https://github.com/tree-sitter-grammars/tree-sitter-markdown/issues/127
-        -- As a result we handle leading spaces here, can remove if this gets fixed upstream
-        local leading_spaces = str.leading_spaces(info.text)
         self.marks:add(true, info.start_row, info.start_col, {
             end_row = info.end_row,
             end_col = info.end_col,

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local M = {}
 
 ---@private
 ---@type string
-M.version = '6.3.5'
+M.version = '6.3.6'
 
 function M.check()
     vim.health.start('render-markdown.nvim [version]')