You mean parenthesis.
On web pages I prefer when it's set with square brackets ([) because placing the chords above never line up correctly in an html page.
For my part, I use a typesetting language---TeX. It's freely available on all platforms (linux, MacOS, MS-Windows).
All my songbooks have been typeset that way (output is pdf).
http://vonbiber.byethost17.com/ukulele/songs.html
I call them "round brackets" and "square brackets", but parentheses works too. I usually do use square brackets, but simply to avoid having to press the shift key, not because I find them easier to read.
Shine On Harvest Moon Jack Norworth & Nora Bayes-Norworth 1938
The [Am] night was mighty [E7] dark so you could [Am] hardly see,
'Cause the [C] moon re[G]fused to [E7] shine
A [Am] couple sittin' [E7] underneath the [Am] willow tree,
For [D7] love, they [G] pine
[Dm] Little maid was [G7] kinda ‘fraid of [Dm] darkness, [G7]
So she [C] said I [G] think I'll [C] go
[D7] Boy began to [G] sigh, [D7] looked up in the [G] sky
And [D7] told the moon his [Am] little tale of [G] woe, [G7] So,
[A7] Shine on, shine on harvest [D7] moon up in the sky
[G] I ain't [G7] had no lovin' since [C] January, [F] February, [C] June, or July
[A7] Snow time ain't no time to [D7] sit outdoors and spoon
So [G] shine on, [G7] shine on harvest [C] moon for [F] me and my [C] gal
I [Am] can't see why a [E7] boy should cry when [Am] by his side
Is a [C] girl he [G]loves so [E7] true;
[Am] All he has to [E7] say is, "Won't you [Am] be my bride,
For [D7] I love [G] you."
But [Dm] why should I be [G7] telling you this [Dm] secret when [G7]
I [C] know that [G] you can [C] guess?
[D7] Harvest moon will [G] smile, [D7] shine on all the [G] while,
[D7] If the little [Am] girl should answer [G] "Yes"! [G7] So,
[A7] Shine on, shine on harvest. . .