Add new operators, keywords

[FreHu]

x += 5.
x -= 5.
x *= 5.
x /= 5.
x &&= 5.

TYPE RANGE OF
CALL FUNCTION foo DESTINATION bar
WITH HEADER LINE
WITH EMPTY KEY

I'm also uniting the scope names for operators to a more general keyword.operator.

VsCode does not have any coloring for operators by default and settings don't seem to support scope inheritance, so you actually have to know what scopes exist in the grammar to customize it properly. Not very user friendly.

Now you will be able to color all operators with a single setting:

"editor.tokenColorCustomizations": {
        "[Default Dark+]": {
            "textMateRules": [
                {
                    "scope": "keyword.operator.abap",
                    "settings": {
                        "foreground": "#d456b9"
                    }
                }
            ]
        }
    }

(I will document this in the plugin repo later)

[larshp]

thanks