This change moves the suggested fixes logic for fillstruct out of the
analysis and into internal/lsp/source. This logic is then used as part
of a new fillstruct command. This command is returned along with the
code action results, to be executed only when the user accepts the code
action.
This led to a number of changes to testing. The suggested fix tests in
internal/lsp doesn't support executing commands, so we skip them. The
suggested fix tests in internal/lsp/source are changed to call
fillstruct directly. A new regtest is added to check the command
execution, which led to a few regtest changes.
Also, remove the `go mod tidy` code action, as it's made redundant by
the existence of the suggested fixes coming from internal/lsp/mod.
Change-Id: I35ca0aff1ace8f0097fe7cb57232997facb516a4
Reviewed-on: https://go-review.googlesource.com/c/tools/+/241983
Reviewed-by: Heschi Kreinick <heschi@google.com>
