[css-shapes] Broken references in CSS Shapes Module Level 1

[dontcallmedom-bot]

While crawling CSS Shapes Module Level 1, the following links to other specifications were detected as pointing to non-existing anchors, which should be fixed:

• https://www.w3.org/TR/css-box-3/#the-css-box-model
• https://www.w3.org/TR/css3-transitions/#animatable-types
• https://www.w3.org/TR/css3-transitions/#animtype-simple-list
• https://www.w3.org/TR/css3-transitions/#animtype-lpcalc

_{This issue was detected and reported semi-automatically by Strudy based on data collected in webref.}