more standard Thy_Load.check_thy for Pure.thy, relying on its header;
pass uses and keywords from Thy_Load.check_thy to Thy_Info.load_thy;
clarified 'ML_file' wrt. Thy_Load.require/provide, which is also relevant for Thy_Load.all_current;
src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
doc-src