Add check for "suspicious" characters

These standalone characters often indicate issues with encoding or
copy/paste in languages with accents like French and Spanish. For
example: foreˆt should be forêt.

It is not possible to fix these issues automatically, but this will
print a warning so you can notify the owner of the data.

csv_metadata_quality/app.py

@@ -31,6 +31,9 @@ def main(argv):
         # Check: invalid multi-value separator
         df[column] = df[column].apply(check.separators)
 
+        # Check: suspicious characters
+        df[column] = df[column].apply(check.suspicious_characters)
+
         # Fix: invalid multi-value separator
         if args.unsafe_fixes:
             df[column] = df[column].apply(fix.separators)