csv-diff: add page (#8520)

pages/common/csv-diff.md

@@ -0,0 +1,16 @@
+# csv-diff
+
+> View differences between two CSV, TSV or JSON files.
+> More information: <https://github.com/simonw/csv-diff>.
+
+- Display a human-readable summary of differences between files using a specific column as a unique identifier:
+
+`csv-diff {{path/to/file1.csv}} {{path/to/file2.csv}} --key={{column_name}}`
+
+- Display a human-readable summary of differences between files that includes unchanged values in rows with at least one change:
+
+`csv-diff {{path/to/file1.csv}} {{path/to/file2.csv}} --key={{column_name}} --show-unchanged`
+
+- Display a summary of differences between files in JSON format using a specific column as a unique identifier:
+
+`csv-diff {{path/to/file1.csv}} {{path/to/file2.csv}} --key={{column_name}} --json`