safer out of bounds

[zricethezav]

Description:

Fixes #1132

Checklist:

• Does your PR pass tests?
• Have you written new tests for your changes?
• Have you lint your code locally prior to submission?

[agmond]

@zricethezav
As noted in #1145, this PR didn't solve the issue.
Maybe you meant to fix the issue as suggested below?

Suggested change

	lineEndIdx := matchInLineIDX + len(f.Match)
	if len(f.Line)-1 <= lineEndIdx {
	lineEndIdx = len(f.Line) - 1
	}
	lineEnd := f.Line[matchInLineIDX+len(f.Match):]
	lineEndIdx := matchInLineIDX + len(f.Match)
	if len(f.Line)-1 <= lineEndIdx {
	lineEndIdx = len(f.Line) - 1
	}
	lineEnd := f.Line[lineEndIdx:]