Fix perf regression for lines counter

[vearutop]

No description provided.

[github-actions]

Lines Of Code

Language	Files	Lines	Code	Comments	Blanks	Complexity	Bytes
Go	5	1050 (-12)	797 (-10)	34	219 (-2)	201 (-6)	22.3K (-240B)

[github-actions]

Go API Changes

# summary
Inferred base version: v0.3.8
Suggested version: v0.3.9

[github-actions]

Unit Test Coverage

total: (statements) 37.5%
changed lines: (statements) 100.0%

Coverage of changed lines

File	Function	Coverage
Total		100.0%
cmd/catp/catp/app.go		100.0%
cmd/catp/catp/app.go:227	cat	100.0%

Coverage diff with base branch

File	Function	Base Coverage	Current Coverage
Total		37.1%	37.5% (+0.4%)
cmd/catp/catp/app.go	cat	70.0%	71.4% (+1.4%)
cmd/catp/catp/app.go	readFile	0.0%	no function