Fix binding name in first README lines

[jlaur]

I found some irregularities in the list of addons, for example:

The only thing I could find within these bindings being different from other bindings was the first heading in the README not ending in "Binding" (case sensitive):

$ find ./bundles/org.openhab.binding.* -maxdepth 1 -type f -name "README.md" -exec sh -c 'head -n 1 "$1" | grep -P -qv "Binding\r?$" && echo "$1"' _ {} \;
./bundles/org.openhab.binding.bluetooth.airthings/README.md
./bundles/org.openhab.binding.bluetooth.am43/README.md
./bundles/org.openhab.binding.bluetooth.bluegiga/README.md
./bundles/org.openhab.binding.bluetooth.bluez/README.md
./bundles/org.openhab.binding.bluetooth.blukii/README.md
./bundles/org.openhab.binding.bluetooth.daikinmadoka/README.md
./bundles/org.openhab.binding.bluetooth.generic/README.md
./bundles/org.openhab.binding.bluetooth.govee/README.md
./bundles/org.openhab.binding.bluetooth.hdpowerview/README.md
./bundles/org.openhab.binding.bluetooth.radoneye/README.md
./bundles/org.openhab.binding.bluetooth.roaming/README.md
./bundles/org.openhab.binding.bluetooth.ruuvitag/README.md
./bundles/org.openhab.binding.freeathome/README.md
./bundles/org.openhab.binding.lgtvserial/README.md
./bundles/org.openhab.binding.modbus.e3dc/README.md
./bundles/org.openhab.binding.modbus.helioseasycontrols/README.md
./bundles/org.openhab.binding.modbus.stiebeleltron/README.md
./bundles/org.openhab.binding.modbus.studer/README.md
./bundles/org.openhab.binding.modbus.sunspec/README.md
./bundles/org.openhab.binding.paradoxalarm/README.md
./bundles/org.openhab.binding.pentair/README.md
./bundles/org.openhab.binding.velux/README.md

Therefore I have fixed these headings to be consistent with others.

[andrewfg]

Velux LGTM

[jsjames]

LGTM

[lolodomo]

LGTM, thank you