chore: improve diagnostics for invalid for loop annotation

[tserg]

What I did

Improve diagnostics for invalid loop variable annotation and add tests for #3596.

Compiling this contract throws an error that does not make sense

@external
def foo():
    for i: uint9 in [1, 2, 3]:
        pass

vyper.exceptions.UnknownType: No builtin or user-defined type named '@exte'. 
  contract "tmp/old_for.vy:1", function "foo", line 1:0 
  ---> 1 @external
  -------^
       2 def foo():

This PR changes the error message to:

vyper.exceptions.UnknownType: No builtin or user-defined type named 'uint9'. Did you mean 'uint96', or maybe 'uint8'?
  contract "tmp/old_for.vy:3", function "foo", line 3:4 
       2 def foo():
  ---> 3     for i: uint9 in [1, 2, 3]:
  -----------^
       4         pass

How I did it

Propagate the annotation source code and For node locations to the annotation and all its child nodes

How to verify it

See tests.

Commit message

chore: improve diagnostics for invalid for loop annotation

Description for the changelog

Improve diagnostics for invalid for loop annotation

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[codecov-commenter]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (ddfce52) 84.22% compared to head (1f476fc) 84.21%.
Report is 1 commits behind head on master.

Files	Patch %	Lines
vyper/ast/pre_parser.py	83.33%	1 Missing and 1 partial ⚠️
vyper/ast/parse.py	95.65%	0 Missing and 1 partial ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3721      +/-   ##
==========================================
- Coverage   84.22%   84.21%   -0.01%     
==========================================
  Files          92       92              
  Lines       13073    13091      +18     
  Branches     2916     2921       +5     
==========================================
+ Hits        11011    11025      +14     
- Misses       1644     1646       +2     
- Partials      418      420       +2     

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[charles-cooper]

i think we can use python_ast.walk here

[charles-cooper]

i think python_ast.increment_lineno might be better here

[charles-cooper]

nice new tests.

i think the annotation is a bit tricky to get right, since you're copying the location of the parent for node into the for target. here's a (contrived) example of where that doesn't work so well:

@external
def foo():
    for i: \
        \
        \
        \
        uint9 in [1, 2, 3]:
        pass

with the current implementation that results in an error message something like

vyper.exceptions.UnknownType: No builtin or user-defined type named 'uint9'. Did you mean 'uint96', or maybe 'uint8'?
  contract "repros/3721.vy:3", function "foo", line 3:4 
       2 def foo():
  ---> 3     for i: \
  -----------^
       4         \

i think what we really want to do is go into the tokens generated by ASTTokens (https://asttokens.readthedocs.io/en/latest/api-index.html#asttokens.ASTTokens.tokens) and modify all of them to have the correct start/end offsets.

[charles-cooper]

i have a solution for #3721 (review). i'll submit it in a follow up PR.