common : process escape sequences in reverse prompts (#3461)

Author: staviq

Diff for: common/common.cpp

@@ -616,6 +616,9 @@ bool gpt_params_parse(int argc, char ** argv, gpt_params & params) {
         process_escapes(params.prompt);
         process_escapes(params.input_prefix);
         process_escapes(params.input_suffix);
+        for (auto & antiprompt : params.antiprompt) {
+            process_escapes(antiprompt);
+        }
     }
 
     return true;