Support properties that include a template variable

[mikewheaton]

Describe the bug
When variables are inserted within properties, the plugin is splitting up the value onto multiple lines.

To Reproduce
Sorting this styled component:

const Avatar = styled.img`
  border-radius: 50%;
  margin-bottom: 16px;
  height: ${AVATAR_SIZE}px;
  width: ${AVATAR_SIZE}px;
`;

Results in:

const Avatar = styled.img`
  border-radius: 50%;
  height: ${AVATAR_SIZE}
  margin-bottom: 16px;
  px;
  px;
  width: ${AVATAR_SIZE}
`;

Expected behavior

const Avatar = styled.img`
  border-radius: 50%;
  height: ${AVATAR_SIZE}px;
  margin-bottom: 16px;
  width: ${AVATAR_SIZE}px;
`;

[mrwwalmsley]

I've done a rewrite that addresses this issue and the other issues that have been filed. Deciding whether I should publish as a separate plugin, or try to merge into this plugin.