Add case sensitivity support to ExprIndicesOf & Cleanup

[Burbulinis]

Problem

The current implementation of the indices of expression always performs case-sensitive string comparisons, without the ability to do otherwise.

Solution

This PR updates the behaviour so that string comparisons now follow the case sensitive option defined in Skript's configuration. As well, it updates usage of the old @Examples annotation to @Example and adds utility methods to StringUtils.

Testing Completed

I don't believe there is a good way to test this. Manual testing has confirmed this works properly.

Supporting Information

Prior to the updates to this expression, index of string in string always used case-sensitive comparisons, so existing scripts that relied on that behaviour may now break if the case sensitive node is false in the configuration.

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Completes: none
Related: none

[Efnilite]

looks nice

[Burbulinis]

I have also renamed the expression from Indices Of to Indices of Value. This is done because I believe there could be confusion between the expression Indices of List which returns the indices of a list or sorted.