fix: make all of source provider config optional

Author: Saghen

lua/blink/cmp/config.lua

@@ -68,8 +68,8 @@
 --- @field enabled_providers? string[] | fun(ctx?: blink.cmp.Context): string[]
 ---
 --- @class blink.cmp.SourceProviderConfig
---- @field name string
---- @field module string
+--- @field name? string
+--- @field module? string
 --- @field enabled? boolean | fun(ctx?: blink.cmp.Context): boolean
 --- @field opts? table
 --- @field transform_items? fun(ctx: blink.cmp.Context, items: blink.cmp.CompletionItem[]): blink.cmp.CompletionItem[]