This should make it somewhat easier to experiment with alternative
representations in the future. To reduce churn, this commit leaves the String
field public, though.
Also, this will allow us to use the default String type to represent the IDL
USVString type, which explicitly forbids unpaired surrogates, ans as such is
a better match to the Rust String type.
Issue #7365 : test cursor position after clearing selection
In textinput test if the cursor is at the correct position when clearing a selection by press an arrow key.
edit_point is always at the end of the selection, should I test when it's at the beginning ?
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