docs: Moved need help section after code snippet

[frgfm]

Following up on #946, this PR introduces the following modifications:

• moved the need help section after the code snippet (otherwise the code example is starting to make less sense 😅)
• moved the image to a release attachment

Any feedback is welcome!

[codecov]

Codecov Report

Merging #959 (223acea) into main (c681273) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #959   +/-   ##
=======================================
  Coverage   94.83%   94.83%           
=======================================
  Files         134      134           
  Lines        5539     5539           
=======================================
  Hits         5253     5253           
  Misses        286      286           

Flag	Coverage Δ
unittests	94.83% <ø> (ø)

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Impacted Files	Coverage Δ
doctr/transforms/modules/base.py	94.59% <0.00%> (ø)

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[felixdittrich92]

Much better 😅 👍