fix pep E303 in all folders starting with [defghi]

[fchapoton]

📚 Description

This fixes all pycodestyle warning about E303 in all folders whose first letter is among defghi.

E303 too many blank lines

📝 Checklist

• I have made sure that the title is self-explanatory and the description concisely explains the PR.
• I have linked an issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[github-actions]

Documentation preview for this PR is ready! 🎉
Built with commit: 874da86

[codecov-commenter]

Codecov Report

Patch coverage has no change and project coverage change: -0.03 ⚠️

Comparison is base (5330147) 88.61% compared to head (874da86) 88.58%.

❗ Current head 874da86 differs from pull request most recent head 2b32a1b. Consider uploading reports for the commit 2b32a1b to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #35244      +/-   ##
===========================================
- Coverage    88.61%   88.58%   -0.03%     
===========================================
  Files         2148     2140       -8     
  Lines       398855   397415    -1440     
===========================================
- Hits        353438   352045    -1393     
+ Misses       45417    45370      -47     

Impacted Files	Coverage Δ
src/sage/data_structures/stream.py	97.47% <ø> (ø)
src/sage/databases/findstat.py	27.47% <ø> (+0.02%)	⬆️
src/sage/databases/knotinfo_db.py	45.61% <ø> (ø)
src/sage/doctest/reporting.py	74.45% <ø> (ø)
src/sage/features/__init__.py	95.18% <ø> (ø)
src/sage/finance/markov_multifractal.py	98.00% <ø> (ø)
src/sage/functions/exp_integral.py	90.24% <ø> (ø)
src/sage/games/hexad.py	86.97% <ø> (ø)
src/sage/games/sudoku.py	100.00% <ø> (ø)
src/sage/geometry/cone.py	93.60% <ø> (ø)
... and 38 more

... and 154 files with indirect coverage changes

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[vbraun]

Merge conflict

[fchapoton]

back to positive after trivial merge