coq-prog-name disregarded and overwritten #869
Description
Assume an environment that has coqtop with some version 8 and rocq with some version 9. After merging PR #841 PG will always run rocq, even if one configures coq-prog-name to "coqtop".
When coq-prog-name is configured to "coqtop", then after visiting the first .v file, coq-prog-name and proof-prog-name both still have the value "coqtop". However, when starting Coq/Rocq when the first line is asserted, both are overwritten to "rocq".
PG should support a feature, where the user can configure the Coq/Rocq binary via file or directory local variables.
Does anybody remember the reason why PG overwrites coq-prog-name?