docs: add degree and coeff

[t-bltg]

Following #677.

[codecov-commenter]

Codecov Report

Merging #735 (c8e3791) into master (ab7e1aa) will decrease coverage by 0.42%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #735      +/-   ##
==========================================
- Coverage   75.82%   75.40%   -0.43%     
==========================================
  Files          23       23              
  Lines        2792     2789       -3     
==========================================
- Hits         2117     2103      -14     
- Misses        675      686      +11     

Impacted Files	Coverage Δ
src/utils.jl	74.80% <ø> (-0.20%)	⬇️
src/array-lib.jl	78.08% <0.00%> (-2.47%)	⬇️
src/wrapper-types.jl	77.50% <0.00%> (-1.25%)	⬇️
src/latexify_recipes.jl	56.11% <0.00%> (-0.72%)	⬇️
src/build_function.jl	74.41% <0.00%> (-0.59%)	⬇️
src/semipoly.jl	90.86% <0.00%> (-0.44%)	⬇️
src/arrays.jl	77.90% <0.00%> (-0.37%)	⬇️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[t-bltg]

@YingboMa, bump.