fix(doc): resolve file descriptor leaks in documentation generators

[CygnusMaximillian]

Description

This PR fixes a subtle file descriptor leak vulnerability within the CLI documentation generator logic (doc/doc.go and doc/man-docs/man_doc.go).

Previously, defer f.Close() was placed after write operations (like io.WriteString), or handled manually in a way that missed early err != nil return paths. If an I/O operation failed mid-way, the function exited prematurely, leaving the file descriptor open and causing potential resource exhaustion.

Changes Made

• doc/doc.go: Moved defer f.Close() to execute immediately after checking os.Create errors, guaranteeing closure on subsequent write failures.
• doc/man-docs/man_doc.go: Replaced manual/conditional closing logic with immediate defer calls for robust resource management.

Verification Results

I have verified these changes locally:

• go build ./... completes successfully.
• go test ./... passes without regressions.

Closes

Closes #991

Screenshots of Tests

also I ran general go test ./... for man_doc.go as there are no dedicated test for it

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 9.34%. Comparing base (60ad0bd) to head (925360c).
⚠️ Report is 186 commits behind head on main.

Files with missing lines	Patch %	Lines
doc/man-docs/man_doc.go	52.63%	4 Missing and 5 partials ⚠️
doc/doc.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             main    #992      +/-   ##
=========================================
- Coverage   10.99%   9.34%   -1.65%     
=========================================
  Files         173     321     +148     
  Lines        8671   16089    +7418     
=========================================
+ Hits          953    1504     +551     
- Misses       7612   14442    +6830     
- Partials      106     143      +37     

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[bupd]

/lgtm

@CygnusMaximillian Thanks for your contribution

[Copilot]

Pull request overview

This PR aims to eliminate file descriptor leaks in the CLI documentation generators by ensuring files created/opened during doc generation are reliably closed on all error paths.

Changes:

• Move defer f.Close() to immediately after os.Create in MarkdownTreeCustom to prevent leaks on write failures.
• Replace manual Close() calls in man page cleanup with defer to ensure closure on early returns.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
doc/doc.go	Registers defer f.Close() immediately after os.Create so write/generation failures don’t leak the output file descriptor.
doc/man-docs/man_doc.go	Switches to deferred closes during man page read/write cleanup to cover early error returns.

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[bupd]

@CygnusMaximillian seems to be valid.