#264 Enable tooltips while typing into function's argument's parentheses

[Erik Hänel]

Enable tooltips while one is typing into argument's parentheses of functions or procedures.

Analysis:
This requires multiple new member functions:

• A function for handling the presentation of the tooltip. This also means that it keeps track of the position of the caret and whether it is inside of the current function. If not, then the tooltip has to vanish
• A function for finding the current parenthesis and whether this is a function/procedure. This function will only search in the current line.
• A function for obtaining the correct tooltip. This may be summarized with the hovering tooltip function
• A function for finding the current argument of the parentheses while typing, i.e. which argument has to be highlighted in the current context

Implementation:
The functionality was implemented as proposed by the analysis. Implementation tests were passed successfully.

Documentation:
Not needed - Self explaining feature.

Tests:
The functionality was tested in production tests. No deviations detected. Functionality implemented successfully.