feat: add option to always show diagnostics

* rename option and add to default config

* combine separate if statements using else if

README.md

@@ -460,6 +460,7 @@ sections = {
       }
       symbols = {error = 'E', warn = 'W', info = 'I', hint = 'H'}
       update_in_insert = false, -- Update diagnostics in insert mode
+      always_visible = false, -- Show diagnostics even if count is 0, boolean or function returning boolean
     }
   }
 }

doc/lualine.txt

@@ -440,6 +440,7 @@ will be.
           }
           symbols = {error = 'E', warn = 'W', info = 'I', hint = 'H'}
           update_in_insert = false, -- Update diagnostics in insert mode
+          always_visible = false, -- Show diagnostics even if count is 0, boolean or function returning boolean
         }
       }
     }

lua/lualine/components/diagnostics/config.lua

@@ -17,6 +17,7 @@ M.symbols = {
 M.options = {
   colored = true,
   update_in_insert = false,
+  always_visible = false,
   sources = { 'nvim_lsp', 'coc' },
   sections = { 'error', 'warn', 'info', 'hint' },
   diagnostics_color = {

lua/lualine/components/diagnostics/init.lua

@@ -83,6 +83,14 @@ function M:update_status()
     info = info_count,
     hint = hint_count,
   }
+
+  local always_visible = false
+  if type(self.options.always_visible) == 'boolean' then
+    always_visible = self.options.always_visible
+  elseif type(self.options.always_visible) == 'function' then
+    always_visible = self.options.always_visible()
+  end
+
   -- format the counts with symbols and highlights
   if self.options.colored then
     local colors = {}
@@ -90,13 +98,13 @@ function M:update_status()
       colors[name] = modules.highlight.component_format_highlight(hl)
     end
     for _, section in ipairs(self.options.sections) do
-      if data[section] ~= nil and data[section] > 0 then
+      if data[section] ~= nil and (always_visible or data[section] > 0) then
         table.insert(result, colors[section] .. self.symbols[section] .. data[section])
       end
     end
   else
     for _, section in ipairs(self.options.sections) do
-      if data[section] ~= nil and data[section] > 0 then
+      if data[section] ~= nil and (always_visible or data[section] > 0) then
         table.insert(result, self.symbols[section] .. data[section])
       end
     end