Improve syntax highlighting with contextual information

[macabeus]

Is your feature request related to a problem? Please describe. A syntax highlighting that express more details on codebase is useful to developer read and understand better the code.

Describe the solution you'd like There are two features on syntax highlighting that I'm missing:

1 - A different color for the arguments

Let's say that we have this code:

*** Keywords ***
User make the selections "${first}" "${second}"
    User select    ${first}
    User select    ${second}

*** Test Cases ***
Selections
    User make the selections "foo" "bar"

Currently the entire line User make the selections "foo" "bar" will have the same color on all characters. Would be useful to foo and bar have a different color, to see better what are the arguments. It's also useful to detect a syntax error.

2 - Keywords should have different colours

Let's say that we have this test case:

Big test case
    User do A
    User do B
    User do more one thing
    Result should be nice

Just reading this test case we don't know what are keywords and what aren't. Would be useful to have distinctions.