MAINT: Simplify `generate_directional_partial_diagrams()` and change to "directional diagrams"

[nawtrey]

• Change name to generate_directional_diagrams() and correct all function calls

• Simplify logic so code isn't so redundant

• Remove unnecessary graph creation for return_edges=True case

• Switch to generating new graph object instead of making copies of base graph

[codecov[bot]]

Codecov Report

Merging #41 (36ef689) into master (f9d0d14) will decrease coverage by 0.02%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #41      +/-   ##
==========================================
- Coverage   98.01%   97.99%   -0.03%     
==========================================
  Files           9        9              
  Lines         757      747      -10     
==========================================
- Hits          742      732      -10     
  Misses         15       15              

Impacted Files	Coverage Δ
kda/calculations.py	99.52% <100.00%> (ø)
kda/diagrams.py	100.00% <100.00%> (ø)

[nawtrey]

I think the verification script still needs to be updated.

[nawtrey]

I don't care about the drop in coverage as this is a pretty obvious code simplification. I should also note that for the return_edges=True case, this does run slightly faster now. There was basically a graph being copied for no reason, so removing that brought the runtime down about 8% for a 117K directional diagram case. Not huge, but worth noting.

Tests are passing, so I'm gonna merge this.