change prompt compression diff replacement text

[jeske]

WHen the prompt compression runs, it seems to replace diffs with something like:

"Compressed diff with 1 SEARCH/REPLACE blocks"

This is terrible, because the AI doesn't know this is a compressed diff, so instead it thinks this is actually the file contents. Then later it tries to perform a file edit based on thinking that was the file contents:

It needs to replace it with something the AI can understand... more like:

<FileRead NOTE="These file contents have been removed from the prompt. If you need the file please re-read it"/>