Change Ruff's text format to show the source code and context by default

[MichaReiser]

Ruff's default text format only shows the file, location, and message of a reported violation without providing any additional context.

crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:8:17: F821 Undefined name `func1`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:8:23: F821 Undefined name `arg1`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:8:33: F821 Undefined name `func2`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:8:39: F821 Undefined name `arg2`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:24:5: F821 Undefined name `long_module`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:25:8: F821 Undefined name `long_module`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:25:68: F821 Undefined name `arg1`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:29:8: F821 Undefined name `xxxxxxxxx`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/trailing_commas_in_leading_parts.py:30:5: F821 Undefined name `xxxxxxxxx`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/tupleassign.py:2:89: E501 Line too long (96 > 88 characters)
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/tupleassign.py:5:35: F821 Undefined name `struct`
crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/tupleassign.py:7:8: F821 Undefined name `call`

This has the advantage that the output is very compact, which is especially useful when there are many diagnostics. However, I have found myself struggling with understanding diagnostics from just the brief (and very long) message. For example the following message:

crates/ruff/resources/test/cpython/Tools/unittestgui/unittestgui.py:107:9: E722 Do not use bare `except`

As a Python beginner, I haven't heard of a bare except before. Showing the source text would help me because I may at least be able to infer that it probably refers to the except without any specific exception, but only if I have the experience on why this might be bad. I recommend showing the suggested fix, if any, to help users understand how to solve the problem.

The part I'm somewhat undecided on is whether we should show the explanation why this is bad. Showing the explanation can be useful to understand the problem but it can bloat every diagnostic quiet a bit.

What's your use case/opinion? Would you find it useful if ruff shows more descriptive diagnostics by default or do you prefer the compact rendering as it is today, and why?

Prior Art

Rome

main.tsx:1:15 [lint/correctness/noUnusedVariables](https://docs.rome.tools/lint/rules/noUnusedVariables)  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This parameter is unused.
  
  > 1 │ function test(a, b) {
      │               ^
    2 │   
    3 │ }
  
  ℹ Unused variables usually are result of incomplete refactoring, typos and other source of bugs.
  
  ℹ Suggested fix: If this is intentional, prepend a with an underscore.
  
    1   │ - function·test(a,·b)·{
      1 │ + function·test(_a,·b)·{
    2 2 │     
    3 3 │   }

• Shows code frame
• Shows additional advices
• Has a link to the rule with more extensive documentation

Clippy

warning: casting `usize` to `u32` may truncate the value on targets with 64-bit wide pointers
  --> crates/ruff/src/message/diff.rs:39:17
   |
39 |         let b = a as u32;
   |                 ^^^^^^^^
   |
   = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ...
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_possible_truncation
   = note: `-W clippy::cast-possible-truncation` implied by `-W clippy::pedantic`
help: ... or use `try_from` and handle the error accordingly
   |
39 |         let b = u32::try_from(a);
   |                 ~~~~~~~~~~~~~~~~

• Shows code frames
• Message explains why this is bad (rather than just what the problem is)
• Has a link to an in-depth explanation

Elm review

• Explains the problem
• Shows the code frame
• Has an explanation on how to fix the problem