docs: document the parse_err_log_level core parameter

Author: denyspozniak

docs/manual/Script-CoreParameters.md

@@ -843,6 +843,20 @@ Example of usage:
 
 ```
 
+### parse_err_log_level
+
+The log level of the errors reported while parsing incoming SIP messages (bad headers, bad Via, CSeq, To or From bodies, unparsable messages). Set it above [log_level](#log_level) to keep scanners and broken clients from flooding the log; other errors are not affected. Takes the same values as [log_level](#log_level).
+
+Default value is `-1` (error level).
+
+Example of usage:
+```opensips
+
+    # log SIP parse errors only when running with log_level = 3 or higher
+    parse_err_log_level = 3
+
+```
+
 ### pi_framework
 
 The path to the XML provisioning framework used by the active PI transport.

utils/vim/opensips.vim

@@ -55,7 +55,7 @@ syn keyword osGlobalParam tcp_max_msg_time abort_on_assert anycast
 syn keyword osGlobalParam log_prefix
 syn keyword osGlobalParam stderror_log_format syslog_log_format
 syn keyword osGlobalParam log_json_buf_size log_msg_buf_size log_ratelimit_period
-syn keyword osGlobalParam log_event_enabled log_event_level_filter
+syn keyword osGlobalParam log_event_enabled log_event_level_filter parse_err_log_level
 syn keyword osGlobalParam shm_memlog_size
 
 " String constants