fix column headers

Author: aekrylov

src/main/java/org/victoria2/tools/vic2sgea/export/CsvExporter.java

@@ -37,7 +37,7 @@ public static void exportCountry(Watch watch, String tag, Path filename) throws
         writer.configureBeanMapping(CountryCsvBean.class, fields.toArray(new String[0]));
         writer.writeHeader(
                 fields.stream()
-                        .map(f -> ExportUtils.COUNTRY_FIELDS.getOrDefault(f, f))
+                        .map(f -> ExportUtils.COUNTRY_FIELDS.getOrDefault(f.replace("country.", ""), f))
                         .toArray(String[]::new)
         );