Update diagnostic virtual text marker

lua/navigator/diagnostics.lua

@@ -112,9 +112,9 @@ local function error_marker(result, ctx, config)
         p = diag.range.start.line
         p = util.round(p * wheight / math.max(wheight, total_num))
         if pos[#pos] and pos[#pos].line == p then
-          local bar = '▆'
-          if pos[#pos] == _NgConfigValues.lsp.diagnostic_scrollbar_sign[2] then
-            bar = '█'
+          local bar = _NgConfigValues.lsp.diagnostic_scrollbar_sign[2]
+          if pos[#pos] == bar then
+            bar = _NgConfigValues.lsp.diagnostic_scrollbar_sign[3]
           end
           pos[#pos] = {line = p, sign = bar, severity = math.min(diag.severity, pos[#pos].severity)}
         else

lua/navigator/util.lua

@@ -27,7 +27,7 @@ M.path_cur = function()
 end
 
 M.round = function(x)
-  return math.floor(x + 0.5)
+  return math.max(0, math.floor(x - 0.5))
 end
 
 function M.get_data_from_file(filename, startLine)