Here is the new patch, I ran a diff between "./python -m pydoc _bisect" before and after my patch, here it is:

13,15c13
<     bisect_left(...)
<         bisect_left(a, x[, lo[, hi]]) -> index
<         
---
>     bisect_left(a, x, lo=0, hi=-1)
25,27c23
<     bisect_right(...)
<         bisect_right(a, x[, lo[, hi]]) -> index
<         
---
>     bisect_right(a, x, lo=0, hi=-1)
32c28
<         beyond the rightmost x already there
---
>         beyond the rightmost x already there.
37,39c33
<     insort_left(...)
<         insort_left(a, x[, lo[, hi]])
<         
---
>     insort_left(a, x, lo=0, hi=-1)
47,49c41
<     insort_right(...)
<         insort_right(a, x[, lo[, hi]])
<         
---
>     insort_right(a, x, lo=0, hi=-1)

So I kept my addition of the missing full stop, and dropped the handwritten signature as Argument Clinic generates it.