Improve error logging for unresolved variables

[RamanaReddy0M]

Proposed changes

• Improve Error logging of unresolved variables #3386

test

✗ go run . -t ~/nuclei-templates/http/token-spray -v

                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.1.0-dev

                projectdiscovery.io

[VER] Started metrics server at localhost:9092
[INF] Current nuclei version: v3.1.0-dev (development)
[INF] Current nuclei-templates version: v9.6.9 (latest)
[WRN] Scan results upload to cloud is disabled.
[INF] New templates added in latest release: 45
[INF] Templates loaded for current scan: 242
[INF] Executing 242 signed templates from projectdiscovery/nuclei-templates
[WRN] Failed 242 requests due to unresolved variables. Use -elabel=UNV to enable unresolved variables logs.

• to toggle

go run . -v -elabel=UNV

Checklist

• Pull request is created against the dev branch
• All checks passed (lint, unit/integration/regression tests etc.) with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[tarunKoyalwar]

implementation lgtm !

$ ./nuclei  -t ~/nuclei-templates/http/token-spray -v  

                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.1.0-dev

		projectdiscovery.io

[VER] Started metrics server at localhost:9092
[INF] Current nuclei version: v3.1.0-dev (outdated)
[INF] Current nuclei-templates version: v9.7.1 (latest)
[WRN] Scan results upload to cloud is disabled.
[INF] New templates added in latest release: 0
[INF] Templates loaded for current scan: 242
[INF] Executing 242 signed templates from projectdiscovery/nuclei-templates
[WRN] Failed 242 requests due to unresolved variables. Use -elabel=UNV to enable unresolved variables logs.
[INF] No results found. Better luck next time!

Notes:

I think we can change statement since this is expected behaviour and not a error
since unresolved behaviour normally happens when template did not match or required variable like password,username was not provided from user

[WRN] Failed 242 requests due to unresolved variables. Use -elabel=UNV to enable unresolved variables logs.

something like

[VER] Skipped 242 Requests due to missing variable in input or request precondition failed due to no match in template

or even better we can seperate these two statements/cases
What do you think ?
cc: @ehsandeep @RamanaReddy0M