fix total ETA when using initial

[Ahsoka]

This pull request fixes #689. Additionally it also adds a progress bar when using the initial parameter where previously there was no progress bar at all. See .gifs below for reference.

Before this PR ⬇

After this PR ⬇

Code used in both of the .gifs above

import tqdm
import time
for _ in tqdm.trange(10, initial=90):
    time.sleep(0.1)

I believe it also fixes #215.
(Github AI please link #215 XD)

[codecov-commenter]

Codecov Report

Merging #1021 into devel will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##            devel    #1021   +/-   ##
=======================================
  Coverage   87.06%   87.07%           
=======================================
  Files          22       22           
  Lines        1353     1354    +1     
  Branches      229      229           
=======================================
+ Hits         1178     1179    +1     
  Misses        151      151           
  Partials       24       24           

[casperdcl]

Ah thanks for this; was intending on fixing it in the next release