chore: update tree

[thinkerou]

if !cond {
}
// else code

instead of

if cond {
} else {
}

[codecov]

Codecov Report

Merging #2371 (0eb2d6b) into master (3b5e861) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2371      +/-   ##
==========================================
- Coverage   98.48%   98.47%   -0.01%     
==========================================
  Files          41       41              
  Lines        1974     1973       -1     
==========================================
- Hits         1944     1943       -1     
  Misses         17       17              
  Partials       13       13              

Impacted Files	Coverage Δ
tree.go	100.00% <100.00%> (ø)

---

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[thinkerou]

@appleboy I don't know why coverage diff failed.