I have to update this pull request as I added a keyfile header for 'workbench' but
wb_project.c: str = g_key_file_get_string(kf, "Workbench", key, NULL);
wb_project saves to 'Workbench' and I don't want to pollute the keyfile space.

Moved this so I could change the Pull request to About this
I checked out geany@98bcbee3b99d71dfcdd9d3556ace9530ceda818d
and built:
build@debian:~/Projects/geany-plugins-remote/geany-plugins$ git log | head
commit bc8d253
No errors raised by make

config.status: creating config.h
config.status: config.h is unchanged
config.status: executing depfiles commands
config.status: executing libtool commands
config.status: executing po-directories commands
config.status: creating po/POTFILES
config.status: creating po/Makefile
make[1]: Leaving directory '/home/build/Projects/geany-plugins-remote/geany-plugins'
Making all in src
make[1]: Entering directory '/home/build/Projects/geany-plugins-remote/geany-plugins/workbench/src'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/build/Projects/geany-plugins-remote/geany-plugins/workbench/src'
make[1]: Entering directory '/home/build/Projects/geany-plugins-remote/geany-plugins/workbench'
make[1]: Nothing to be done for 'all-am'.
make[1]: Leaving directory '/home/build/Projects/geany-plugins-remote/geany-plugins/workbench'

Created a Workbench, then created a project, then added a project to workbench, then closed and reopened geany.

Both the project and the workbench opened.

This is the only critical in the geany --verbose log, but it appears to be unrelated to the changes.
(geany:109669): Workbench-CRITICAL **: 09:18:59.395: plugin_workbench_on_doc_close: assertion 'doc != NULL && doc->file_name != NULL' failed

Closes #1226
Fixes #1561
Contributed under GNU GENERAL PUBLIC LICENSE Version 2