Migrating from Sinth 4

Most Sinth 4 code compiles unchanged. Things to check:

Sinth 4	Sinth 5
page at the top of every page	removed: delete the line (E0104). Every file in pages/ is a page; move pages that lived elsewhere into pages/
dist/pages/index.html	dist/index.html: pages are now relative to pages/
var int x	var num x (int still works with a warning)
== was loose	== is strict: 1 == "1" is a compile error
"$title" inside component strings	use the parameter directly: { title } or f"{title}"
event handler strings like onClick: "handler"	onClick: handler or onClick: handler() (strings are now a compile error, E0351)
for k, v in obj (key, value)	for value, index, key in obj
sharedRuntime, inlineJS, inlineCSS	removed: splitting and bundling are automatic
import SinthUI (CSS only)	still works; it now also provides real components (sinth:ui)
sinthRender() in scripts	still works; usually unnecessary in Sinth handlers
RawHTML(content: ...)	unchanged; warns when the content is dynamic
fullscreen: attribute	removed; use document.documentElement.requestFullscreen()

Run sinth check after upgrading. It reports every incompatibility with its location.