refactor: simplify zk file completion

dots/.config/nvim/lua/zk/cmp.lua

@@ -13,13 +13,19 @@ local function get_markdown_files(base)
   return items
 end
 
+function source:get_keyword_pattern()
+  return "[%w%./%-]*"
+end
+
 function source:complete(params, callback)
   local cursor_before_line = params.context.cursor_before_line
   local cursor_after_line = params.context.cursor_after_line or ""
 
-  local trigger = cursor_before_line:match("%[[^%]]*%]%(([^)]*)$")
+  if not cursor_before_line:match("%[[^%]]*%]%(") then
+    callback({})
+    return
+  end
 
-  if trigger ~= nil then
   local items = get_markdown_files(".")
   local next_char = cursor_after_line:sub(1, 1)
 
@@ -32,9 +38,6 @@ function source:complete(params, callback)
   end
 
   callback(items)
-  else
-    callback({})
-  end
 end
 
 function source:get_trigger_characters()