docs(chips): improve documentation for md-chip-remove directive
docs(chips): improve documentation for md-chip-remove directive

* Marks `md-remove-chips` directive as an attribute in the Docs.
* Updates the example to work and match the demos.

Closes #8834.

Closes #8835

marekmicek/material,crisbeto/material,pwistbac/material,daniel-nagy/material,ServiceManagementGroup/material,ilovett/material,vertazzar/material,gkalpak/material,vertazzar/material,SamDLT/material,Frank3K/material,imjoeco/material,bluebirdtech/material,ilovett/material,Splaktar/material,ServiceManagementGroup/material,clshortfuse/material,bluebirdtech/material,profoundry-us/material,crisbeto/material,crisbeto/material,graingert/material,bluebirdtech/material,welkinhealth/material,Frank3K/material,miguelcobain/material,oostmeijer/material,marekmicek/material,graingert/material,j3ski/material,pwistbac/material,vertazzar/material,daniel-nagy/material,hayloft/material,gkalpak/material,hayloft/material,SamDLT/material,Splaktar/material,bluebirdtech/material,clshortfuse/material,gkalpak/material,j3ski/material,angular/material,imjoeco/material,imjoeco/material,Splaktar/material,marekmicek/material,j3ski/material,SamDLT/material,david-gang/material,SamDLT/material,graingert/material,miguelcobain/material,gkalpak/material,vertazzar/material,welkinhealth/material,hayloft/material,daniel-nagy/material,marekmicek/material,ServiceManagementGroup/material,DevVersion/material,oostmeijer/material,oostmeijer/material,miguelcobain/material,profoundry-us/material,Splaktar/material,angular/material,pwistbac/material,pwistbac/material,miguelcobain/material,graingert/material,welkinhealth/material,david-gang/material,welkinhealth/material,ilovett/material,ilovett/material,ServiceManagementGroup/material,hayloft/material,david-gang/material,daniel-nagy/material,Frank3K/material,clshortfuse/material,imjoeco/material,DevVersion/material,profoundry-us/material,clshortfuse/material,oostmeijer/material,DevVersion/material,angular/material,Frank3K/material,angular/material,crisbeto/material,j3ski/material,david-gang/material,DevVersion/material,profoundry-us/material