It would be nice to render the environment variables in the failed command

[xonixx]

Rationale

It would be convenient to be able to take a command and run it separately to debug. Now due to the variable in use - this requires additional actions to replace it with actual value.

tests/32_calls.tush:83: $ ./$MAKESURE -f tests/32_calls_pg.sh c
--- expected
+++ actual
@@ -2,5 +2,5 @@
 |   goal 'pg@a_val@b_val' ...
 | pg body: a_val b_val
 |   goal 'pg@a_val@b_val' ...
-| pg body: a_val b_val1
+| pg body: a_val b_val