Hello,

I'm the user that run into this bug, the exact output of the command are:

 > C-h v eldoc-documentation-function RET

eldoc-documentation-function is a variable defined in ‘eldoc.el’.
Its value is ‘ignore’
Original value was ‘eldoc-documentation-default’
This variable has an alias: ‘eldoc-documentation-strategy’.

 > C-h v eldoc-documentation-strategy RET

eldoc-documentation-strategy is a variable defined in ‘eldoc.el’.
Its value is ‘ignore’
This variable is an alias for ‘eldoc-documentation-function’.
This variable is obsolete since eldoc-1.1.0; use 
‘eldoc-documentation-function’ instead.

If it helps to add information to what Alex said.