fix(settings): diagnostics_level should be all upper case

Signed-off-by: Jint-lzxy <[email protected]>

lua/core/settings.lua

@@ -41,8 +41,8 @@ settings["diagnostics_virtual_text"] = true
 -- Priority: `Error` > `Warning` > `Information` > `Hint`.
 --  > e.g. if you set this option to `Warning`, only lsp warnings and errors will be shown.
 -- NOTE: This entry only works when `diagnostics_virtual_text` is true.
----@type "Error"|"Warning"|"Information"|"Hint"
-settings["diagnostics_level"] = "Hint"
+---@type "ERROR"|"WARN"|"INFO"|"HINT"
+settings["diagnostics_level"] = "HINT"
 
 -- Set it to false if you don't use nvim to open big files.
 ---@type boolean