fix links; added lint/test docs

aider/website/docs/usage/lint-test.md

@@ -0,0 +1,59 @@
+---
+parent: Usage
+nav_order: 900
+description: Automatically fix linting and testing errors.
+---
+
+# Linting and testing
+
+Aider can automatically lint and test your code
+every time it makes changes.
+This helps identify and repair any problems introduced
+by the AI edits.
+
+## Linting
+
+Aider comes with built in linters for 
+[most popular languages](/docs/languages.html)
+and will automatically lint code in these languages.
+
+Or you can specify you favorite linter
+with the `--lint-cmd <cmd>` switch.
+The lint command should accept the filenames
+of the files to lint. 
+If there are linting errors, aider expects the
+command to print them on stdout/stderr
+and return a non-zero exit code.
+This is how most linters normally operate.
+
+## Testing
+
+You can configure aider to run your test suite
+after each time the AI edits your code
+using the `--test-cmd <cmd>` switch.
+
+Aider will run the test command without any arguments.
+If there are test errors, aider expects the
+command to print them on stdout/stderr
+and return a non-zero exit code.
+This is how most test tools normally operate.
+
+## Compiled languages
+
+If you want to have aider compile code after each edit, you
+can use the lint and test commands to achieve this.
+
+- You might want want to recompile each file which was modified
+to check for compile errors.
+To do this,
+provide a `--lint-cmd` which both lints and compiles the file.
+You could create a small shell script for this.
+- You might want to rebuild the entire project after files
+are edited to check for build errors.
+To do this,
+provide a `--test-cmd` which both builds and tests the project.
+You could create a small shell script for this.
+Or you may be able to do something as simple as
+`--test-cmd dotnet build && dotnet test`.
+
+