Do not duplicate words between property and colon

[wahidrizka]

A word between a property and its colon gets into the output twice:

safeParse('a {\n  font-size\n  color: red;\n  margin-left: 10px;\n}').toString()
// 'a {\n  font-size\n  color: red;color\n  margin-left: 10px;\n}'

Parser#decl() keeps such words in raws.between and calls unknownWord() for them. The safe parser's unknownWord() adds them to this.spaces too, so they also get into the raws.before of the next node or the raws.after of the parent.

It happens while typing a new property above an existing one. Stylelint parses CSS with this parser when fixing (--fix in 16.x, --fix=lax in 17.x) and writes the output back. After stylelint --fix (16.26.1) on the CSS above, Chrome 154 stops applying margin-left, because the copied color and margin-left: 10px read as one invalid declaration.

Now decl() clears this.spaces after super.decl(). init() empties it when the declaration starts, so only this copy is there. I added a toString() check to the fixes 2 properties in safe mode test. It fails on main with a { color one: white;one one }. pnpm test passes.