make cursor position modifiable from external packages

[digitallyserviced]

for #892
@paololazzari

in case @rivo feels frisky...
#893

if he doesn't feel frisky...

# for just this addition... (overkill to redirect to repo for just one patch)
go mod edit -replace github.com/rivo/tview=github.com/digitallyserviced/tview@input-field-cursor-pos

# for future edits and your own local version...  (you will inevitably end up doing to tview because reasons)
cd YOURPROJECTDIR
mkdir pkgs
git clone https://github.com/rivo/tview pkgs/tview
cd pkgs/tview
git remote add digipatch https://github.com/digitallyserviced/tview
git pull digipatch input-field-cursor-pos
cd ../..
go mod edit -replace github.com/rivo/tview=YOURPROJECTDIR/pkgs/tview
go get
go mod vendor