🤖 remove outdated Copilot output handling instructions

Author: jorenham

.github/copilot-instructions.md

@@ -1,14 +1,5 @@
 # Copilot Instructions for scipy-stubs
 
-Whenever you run a command in the terminal, pipe the output to a file, `output.txt`,
-that you can read from. Do not attempt to read the output of commands from the terminal
-directly, as Copilot will not be able to read it correctly. Make sure to overwrite each
-time so that it doesn't grow too big. There is a bug in the current version of Copilot
-that causes it to not read the output of commands correctly. This workaround allows you
-to read the output from the temporary file instead. Be sure to delete `output.txt` after
-you are done, as it is not included in `.gitignore`, and might contain sensitive
-information.
-
 ## Type annotations
 
 Use `A | B` instead of `Union[A, B]`.