Doc formating

[pv42]

Some doc improvements mostly based on the 2 lints bellow. Additionally the parser::generate() function doc had references to things that do not apply anymore (message conversion between dialects, protobuf (?)). There are no functional changes.

clippy::doc_link_code

• merge code fragments that were next to each other using <code> instead of multiple ``
• enable lint

clippy::doc_paragraphs_missing_punctuation

• apply lint for all functions, but skip over fields, structs, etc. unless the doc was already a sentence
• adjusted comment for function to build proper sentences (when required)
• don't enble the lint since it triggers in cases where punctuation would not make sence e.g. struct fields like system_id