pub const FILE_DIR: &str = "$__skif_file_dir__";Expand description
What the directory of the calling file reads as in the cwd option of an ImportedCall that the file’s own
location computes (__dirname, import.meta.dirname, path.join(__dirname, 'fixtures')), followed by / and the
path relative to the file’s directory ($__skif_file_dir__/./fixtures). command_in_call_dir changes to it, and
place_file_dir puts the file’s directory in its place.