docs: note that deno task ** recurses into node_modules

Author: bartlomieju

runtime/reference/cli/task.md

@@ -580,6 +580,23 @@ echo data[0-9].csv
 
 The supported glob characters are `*`, `?`, and `[`/`]`.
 
+:::caution
+
+Because `globstar` is enabled by default (see [Shell options](#shell-options)),
+`**` recurses into **all** descendant directories, including `node_modules`.
+This differs from some interactive shells where `**` is not recursive unless
+explicitly enabled, so a task like `deno check **/*.ts` can expand to far more
+files than the same command typed in your terminal, sweeping in dependency
+files. That can lead to errors such as `Argument list too long` or type-checking
+files you didn't intend to.
+
+For `deno check` and `deno fmt`, prefer running them without glob arguments and
+using the [`exclude`](/runtime/fundamentals/configuration/) option in your
+`deno.json` (`node_modules` is excluded by default), or disable recursion for
+the task with `shopt -u globstar`.
+
+:::
+
 ### Shell options
 
 `deno task` supports shell options in Deno 2.6.6 and above to control glob