Add path information to parse errors originating from included files.

[squell]

Closing #806

[codecov]

Codecov Report

Attention: 31 lines in your changes are missing coverage. Please review.

Comparison is base (2fa9234) 57.36% compared to head (a392c00) 57.27%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/sudoers/mod.rs	39.47%	23 Missing ⚠️
src/sudo/mod.rs	0.00%	6 Missing ⚠️
src/visudo/mod.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #815      +/-   ##
==========================================
- Coverage   57.36%   57.27%   -0.10%     
==========================================
  Files          74       74              
  Lines       10559    10583      +24     
==========================================
+ Hits         6057     6061       +4     
- Misses       4502     4522      +20     

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[squell]

Note: there are still a few places where we don't provide "location information" (i.e. semantic errors, that pop up during semantic analysis). Providing those would require adding positional information to the AST in a few place. We could do that, but that should be a separate issue.

[japaric]

changes look good to me. it would be nice to have an e2e-test that checks that the error message does contain the expected information (file location)

[rnijveld]

I've added an issue (#827) to add the tests later