imatrix : Add --parse-special for enabling parsing of special tokens in imatrix calculation (#13389)

* Add --parse-special for enabling parsing of special tokens in imatrix calculation

* whitespace

common/common.h

@@ -409,6 +409,7 @@ struct common_params {
 
     bool process_output = false; // collect data for the output tensor
     bool compute_ppl    = true;  // whether to compute perplexity
+    bool parse_special  = false; // whether to parse special tokens during imatrix tokenization
 
     // cvector-generator params
     int n_pca_batch = 100;