Improve content on Lp norms.

[rodrigogiraoserrao]

This PR addresses this APL Cultivation message.

We add three functions to complement the already existing entry (2*∘÷⍨1⊥2*⍨-)⍤1⍤1 99⍨Nm:

• two dyadic functions that compute L1 and L2 distances between two points;
• a monadic function that computes pair-wise L1 distances between points in the rows of a matrix Nm;

For these 4 functions we add TIO links and enrich the keywords with stylized "Lp" symbols: ℓ2 ℓ-2 ℓ₂ L²

Furthermore, we add stylized "Lp" symbols to 3 entries that were related to Lp norms.

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• from your APL session, check that Test'path/aplcart/table.tsv' returns 1