RegEx Documentation lacks defined Modes

Within the documentation for the RegEx class, there is no mention of flags, conditions, or modes to alter how a Regex pattern functions (ie: case insensitive mode, or multi-line mode). The only way to use these different modes is by using the `(?%)` format *(substituting the % for the specified modes). It is difficult to find this functionality without prior knowledge within Godot and in the PCRE2 documentation.

I believe there should be an addition inside Godot's RegEx class documentation demonstrating how to use modes to avoid this confusion for people new to Regex or unfamiliar with this way to declare modes.