New T585: Hereditarily connected + not empty ==> contractible.
Removed old T584 [indiscrete + not empty ==> contractible], which can be deduced from the new result.
(I reshuffled the old T585 [contractible ==> not empty] to become T584. That's just cosmetic, so the basic results for Contractible show up first in https://topology.pi-base.org/properties/P000199/theorems. Sorry about any confusion.)
As discussed in #925.
New T585: Hereditarily connected + not empty ==> contractible.
Removed old T584 [indiscrete + not empty ==> contractible], which can be deduced from the new result.
(I reshuffled the old T585 [contractible ==> not empty] to become T584. That's just cosmetic, so the basic results for Contractible show up first in https://topology.pi-base.org/properties/P000199/theorems. Sorry about any confusion.)