Fix Reviewdog format, add docs

Author: alexpdp7

README.md

@@ -2,4 +2,10 @@ This is a proof-of-concept Python library to format errors.
 
 It is based on the [Reviewdog Diagnostic Format](https://github.com/reviewdog/reviewdog/tree/master/proto/rdf).
 
+pyrde can:
+
+* Generate text errors on the terminal.
+* Generate CSV files with errors for statistical analysis.
+* Generate [pull request comments](https://github.com/alexpdp7/pyrde/pull/1) using Reviewdog.
+
 See [the example directory](example/) for an example.

example/README.md

@@ -5,3 +5,11 @@ $ bad_lines example.txt --error-format csv
 message,severity,path,start_line,start_column,end_line,end_column,code,code_url,line
 Line 'foo.' contains foo,ERROR,example.txt,2,,,,BAD_LINE,,foo.
 ```
+
+To use Reviewdog to review PRs:
+
+```
+$ bad_lines --error-format reviewdog example/example.txt  | CI_PULL_REQUEST=1 CI_REPO_OWNER=alexpdp7 CI_REPO_NAME=pyrde CI_COMMIT=e1da9791bdf4406d60ee1d38ced1095e4d24c4e3 REVIEWDOG_GITHUB_API_TOKEN=... reviewdog -f rdjsonl -diff="git diff FETCH_HEAD" -guess -reporter=github-pr-review -name bad_lines
+```
+
+See <https://github.com/alexpdp7/pyrde/pull/1> for the results.

example/example.py

@@ -19,7 +19,7 @@ def main():
         content = file.read_text()
         bad_lines = [(number, line) for number, line in enumerate(content.splitlines()) if "foo" in line]
         for number, line in bad_lines:
-            db.add_diagnostic("Line '{line}' contains foo", {"line": line}, diagnostics.Severity.ERROR, file, number, None, None, None, "BAD_LINE", None)
+            db.add_diagnostic("Line '{line}' contains foo", {"line": line}, diagnostics.Severity.ERROR, file, number + 1, None, None, None, "BAD_LINE", None)
             errors = True
 
     db.finish()