Refine Prism.js highlighting of Tolk code blocks

[novusnota]

Let's:

1. Highlight less when we're not sure of the language
2. Add additional checks when keywords from different languages match. Like, fun and struct exist both in Tact and Tolk, whereas @inline and similar attributes exist only in Tolk, while Tact uses inline as a keyword.
3. Not use location.href — this is a poor heuristic that limits the proper use of code blocks to a single language, which renders possible TL-B clarifications and cross-language comparisons obsolete: think FunC vs. Tolk for users of FunC, or even Tolk vs. Aiken (Cardano) for people from other blockchains that use domain-specific languages which aren't Rust-based or Solidity.