Feature/unicode support

[m-messer]

Implemented unicode greek letter support for symbolic expressions and physical quantities.

Supported greek letters in Symbolic Expressions:

• Alpha — Α
• alpha — α
• Beta — Β
• beta — β
• Gamma — Γ
• gamma — γ
• Delta — Δ
• delta — δ
• Epsilon — Ε
• epsilon — ε
• Zeta — Ζ
• zeta — ζ
• Eta — Η
• eta — η
• Theta — Θ
• theta — θ
• Iota — Ι
• iota — ι
• Kappa — Κ
• kappa — κ
• Lambda — Λ
• lamda — λ (intentional spelling to avoid conflict with Python’s lambda)
• Mu — Μ
• mu — μ
• Nu — Ν
• nu — ν
• Xi — Ξ
• xi — ξ
• Omicron — Ο
• omicron — ο
• Pi — Π
• pi — π
• Rho — Ρ
• rho — ρ
• Sigma — Σ
• sigma — σ
• Tau — Τ
• tau — τ
• Upsilon — Υ
• upsilon — υ
• Phi — Φ
• phi — φ
• Chi — Χ
• chi — χ
• Psi — Ψ
• psi — ψ
• Omega — Ω
• omega — ω

Supported Greek letters in Physical Quantities:

• micro - μ
• Ohm - Ω
• degree - θ

[peterbjohnson]

• I don't think theta is a unit of angle. It's a symbol used as a variable representing an angle. Unless you can convince me otherwise, I think that needs removing?
• you could consider the degree symbol though? https://www.degreesymbol.net/
• Greek letters often have alternatives, such as \varepsilon, curly theta, etc. You could add them wherever you can find some
• There's an LLM relic in the PR description

[m-messer]

Thanks, updated the PR description (I didn't want to convert a Python list to a bullet list manually.) Switched to the degree symbol. Added variant Unicode symbols.