Hcl Fmt Diff No External Binary

hcl fmt --diff no longer requires the diff binary

Previously, terragrunt hcl fmt --diff spawned a diff process discovered in $PATH to render its output. This made it incompatible with minimal container images and Windows installations where that binary was unavailable.

The flag now produces unified diff output without depending on any external binary.

Note that the output is not byte-identical to GNU diff -u. Each file diff is now preceded by a diff old/<path> new/<path> header line, and the ---/+++ lines no longer include a trailing timestamp. Scripts that parsed the previous output may need small adjustments.