fix(selector-parser): lost of first non space of a descendant combinator

[idoros]

This PR fixes an issue for descendant selectors that start with a non space character, like newline.

Before this fix the combinator node would be build with with a space character as the value and after that includes any additional characters after the first one.

for example:

.a/*newline+space+newline*/

.b {}

would output a descendant combinator with {value: , after: \n }, losing the initial newline.