New lemmas about improper integrals and other things

prefer sign-agnostic conversion following bit structure

tuned for readability and got small performance improvement

bring some code equations into natural order

added missing colon

clarified signature;

clarified signature;

more direct support for "command_span" markup property "is_begin";

clarified signature;

misc tuning and clarification;

clarified signature;

clarified code setup

moved / rearranged lemma

eliminate code drop: declarations where none needed

internal setting to identify pointless code drop: declarations

clarified colors, following d6a14ed060fb;

more comments;

tuned;

tuned;

back to more basic defaults, independently on the accidental L&F: e.g. relevant for editor_style=false, and session_graph.pdf;

proper default colors (amending e840461d5370): e.g. relevant for session_graph.pdf;

eliminate odd Unicode characters (amending e9f3b94eb6a0, b69e4da2604b, 8f0b2daa7eaa, 8d1e295aab70);

clarified natural decl_ord vs. slightly odd merge_decl_ord, following the historic status-quo of 53e56e6a67c3, which originally stems from c06d01f75764;

clarified merge order: accurately reproduce the stable status-quo from 53e56e6a67c3 --- e.g. relevant for smt proof reconstruction in (line 6705 of "$AFP/Modular_arithmetic_LLL_and_HNF_algorithms/HNF_Mod_Det_Soundness.thy") of AFP/f1299d4f896c;

clarified decl_ord wrt. kind_ord;

more diagnostic operations;

more robust treatment of impossible case;

clarified name and status of auxiliary operation

moved lemma

added lemma

merged

Complex analysis lemmas