teach-pui => pui-materials

added input validation explanation

minor

updated algorithm examples

update lecture js example

Merge branch 'main' of https://github.com/interactive-structures/pui-materials

Update 1.1-html-structure.html

update css lecture examples

Merge branch 'main' of https://github.com/interactive-structures/pui-materials

updated lecture css

Update demo link (replace teach-pui with pui-materials)

Update demo link (replace teach-pui with pui-materials)

Update demo link (replace teach-pui with pui-materials)

Fix demo link (replace teach-pui with pui-materials

Fix GitHub Page Link for puinote-lab01/puinote-start