feat: error map

[charles-cooper]

What I did

add an error map to source_map output. this makes it easier for downstream tooling to detect why a revert was issued (without having to rely on heuristics or explicit returndata). this also paves the way for brownie-style dev revert strings to be supported by at the language level.

How I did it

How to verify it

Commit message

Commit message for the final, squashed PR. (Optional, but reviewers will appreciate it! Please see our commit message style guide for what we would ideally like to see in a commit message.)

Description for the changelog

Cute Animal Picture

[codecov-commenter]

Codecov Report

Merging #2939 (443db30) into master (7f37992) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2939      +/-   ##
==========================================
- Coverage   88.32%   88.31%   -0.01%     
==========================================
  Files          97       97              
  Lines       10771    10784      +13     
  Branches     2565     2568       +3     
==========================================
+ Hits         9513     9524      +11     
- Misses        800      802       +2     
  Partials      458      458              

Impacted Files	Coverage Δ
vyper/codegen/arithmetic.py	75.75% <100.00%> (+0.44%)	⬆️
vyper/codegen/core.py	84.90% <100.00%> (+0.02%)	⬆️
vyper/codegen/ir_node.py	92.38% <100.00%> (+0.07%)	⬆️
vyper/codegen/module.py	94.39% <100.00%> (ø)
vyper/codegen/stmt.py	88.16% <100.00%> (ø)
vyper/ir/compile_ir.py	93.47% <100.00%> (+0.03%)	⬆️
vyper/ir/optimizer.py	95.03% <100.00%> (+0.01%)	⬆️
vyper/cli/vyper_ir.py	0.00% <0.00%> (ø)

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[tserg]

LGTM