fix(release): restore proper newline after New Contributors section

[jdx]

Summary

• Fixes the missing newline after the New Contributors section
• Includes regenerated CHANGELOG.md to verify the fix works correctly

Problem

The previous fix (#6195) removed too much whitespace. While it correctly fixed the extra blank line between commits and the New Contributors section, it also removed the newline after the New Contributors section, causing it to run directly into the next version header.

In PR #6192, you can see the problem where the New Contributors line runs directly into the next version:

- @elvismacak made their first contribution## [2025.9.0]...

Solution

Changed line 51 in cliff.toml from {% endif -%} to {% endif %} to preserve the newline after the New Contributors section.

Verification

The CHANGELOG.md has been regenerated and included in this PR to verify the formatting is correct:

• ✅ No extra blank lines between commits within sections
• ✅ No extra blank lines before New Contributors heading
• ✅ Proper blank line preserved after New Contributors section

You can see in the included CHANGELOG.md that the formatting is now clean and consistent throughout.

Test plan

• Generated CHANGELOG.md with git cliff -o CHANGELOG.md
• Verified New Contributors sections have proper spacing
• Checked that version headers are properly separated
• Verify the next release generates properly formatted release notes

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR fixes a formatting issue in the changelog generation template where the New Contributors section was missing a newline, causing it to run directly into the next version header. The fix involves restoring proper whitespace handling in the Jinja template.

• Corrects template whitespace control in cliff.toml to preserve newline after New Contributors section
• Includes regenerated CHANGELOG.md to verify the fix works correctly

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[jdx]

this is super annoying, I can't get the changelog stuff to work locally

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.1 x -- echo	19.3 ± 0.7	18.4	26.4	1.00 ± 0.04
mise x -- echo	19.2 ± 0.4	18.4	20.6	1.00

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.1 env	18.5 ± 0.4	17.9	20.6	1.00
mise env	18.5 ± 0.4	17.9	23.5	1.00 ± 0.03

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.1 hook-env	18.1 ± 0.4	17.4	21.3	1.00
mise hook-env	18.3 ± 0.4	17.6	20.4	1.01 ± 0.03

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.1 ls	16.7 ± 0.5	15.9	20.6	1.00
mise ls	16.8 ± 0.4	16.0	18.5	1.01 ± 0.04

xtasks/test/perf

Command	mise-2025.9.1	mise	Variance
install (cached)	166ms	✅ 102ms	+62%
ls (cached)	63ms	62ms	+1%
bin-paths (cached)	67ms	66ms	+1%
task-ls (cached)	475ms	489ms	-2%

✅ Performance improvement: install cached is 62%