lexer: Putback non-numerical token in number scanning

Signed-off-by: Ian Moffett <ian@mirocom.org>

core/lexer.c

@@ -386,6 +386,7 @@ lexer_scan_num(struct rifle_state *state, int lc, struct token *tok)
         }
 
         if (!isxdigit(c) && c != '_') {
+            lexer_putback(state, c);
             buf[buf_ind] = '\0';
             break;
         }