Optimize the Select Syntax Scheme dialog

[liangjiancang]

When "Auto-select by filename extension" is checked, the best Scheme detected should be displayed at the first or third position (after "2nd Common Base").

In the current version, if user temporarily switch to "Common Base", then switching back to the "correct" scheme requires user finding the correct one in a very long list.

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For example, with an .html file:

current:

expected: