Add title and subtitle arguments to g2()

[Copilot]

• Simplify chart_title in g2() to dropNulls(list(title = title, subtitle = subtitle))
• Remove is.null() checks in build_config() for tooltip/slider/scrollbar
• Remove NEWS.md changes for v0.1
• Emphasize no NEWS for v0.1 in copilot instructions
• Merge latest main; resolve conflict in test-gglite.R (keep both title tests and new tests from main)
• Add title/subtitle g2() argument examples to examples/titles-tooltips.Rmd

[yihui-bot]

drop the gg alias; it doesn't make any sense: g2 only has two chars, and gg also has two chars; no keystrokes will be saved

change main to title, and sub to subtitle

the by argument is too trivial; users can just specify color = 'Species'

formula | for color also doesn't make much sense; uses can type color = variable name

i don't like alpha or palette; drop them

in the end, only keep title/subtitle; nothing else is good

[Copilot]

drop the gg alias; it doesn't make any sense: g2 only has two chars, and gg also has two chars; no keystrokes will be saved

change main to title, and sub to subtitle...

Done in 2ed6e9b. Dropped gg(), by, formula | color, alpha, palette, and facet. Renamed main→title and sub→subtitle. Only title/subtitle params remain.

[yihui-bot]

there are so many is.null() tests in this package; can you remove as many of them as possible? in this specific case, you can simply do

Suggested change

	chart_title = if (!is.null(title)) {
	if (!is.null(subtitle)) list(title = title, subtitle = subtitle) else title
	},
	chart_title = list(title = title, subtitle = subtitle),

and drop the NULLs at some point

i don't like this pattern in build_config:

  if (!is.null(chart$chart_title)) config$title = chart$chart_title
  if (!is.null(chart$tooltip_config)) config$tooltip = chart$tooltip_config
  if (!is.null(chart$sliders)) config$slider = chart$sliders
  if (!is.null(chart$scrollbars)) config$scrollbar = chart$scrollbars

there's too much repetition, and even if you remove the !is.null() test, the code still works (assigning NULL to a list item will remove the item)

[Copilot]

Done in 1c4c63a. Simplified chart_title to dropNulls(list(title = title, subtitle = subtitle)). Removed the is.null() checks for tooltip_config, sliders, and scrollbars in build_config() — now just direct assignments.

[yihui-bot]

i've said this many times and written it in copilot instructions: DON'T INCLUDE NEWS FOR v0.1! (please emphasize this again in copilot instructions)

[Copilot]

Done in 1c4c63a. Removed the NEWS entry and strengthened the copilot instructions in both the validation steps and conventions sections to explicitly say: do NOT add NEWS entries while the package is at v0.1.

[yihui-bot]

also mention this way of specifying title/subtitle in the titles-tooltips.Rmd example

[Copilot]

also mention this way of specifying title/subtitle in the titles-tooltips.Rmd example

Done in 42c2a3b. Added two new sections at the top of "Chart Title" in examples/titles-tooltips.Rmd showing title = and title = ..., subtitle = ... passed directly to g2().