Add motion-1.vim

See also: http://www.w3.org/TR/motion-1/

after/syntax/css/motion-1.vim

@@ -0,0 +1,2 @@
+syn match cssFontProp contained "\<motion\(-\(path\|offset\|rotation\)\)\=\>"
+syn region cssFunction contained matchgroup=cssFunctionName start="\<path\s*(" end=")" oneline keepend

after/syntax/html.vim

@@ -49,4 +49,5 @@ syn include @htmlCss syntax/css/css-variables.vim
 syn include @htmlCss syntax/css/css-will-change-1.vim
 syn include @htmlCss syntax/css/css-writing-modes-3.vim
 syn include @htmlCss syntax/css/html5-elements.vim
+syn include @htmlCss syntax/css/motion-1.vim
 syn include @htmlCss syntax/css/selectors4.vim