Add additional hard link notice to FirstRunImportFromStable

[smallketchup82]

There's been confusion on whether lazer duplicates files and uses up double the disk space when importing files from stable to lazer.

While a notice does already exist serving this purpose, this only shows up once a path to a stable installation is selected AND validated. This clearly isn't enough as there's still people from today, 10 days ago, and much later asking if lazer duplicates disk space when importing from stable.

This PR adds an extra sentence to the description of the import page on the first run overlay, letting users know that hard links are used to effectively share files between stable and lazer when possible. This should give the user two notices that hard links can be utilized, hopefully putting more minds at ease.

Feel free to close if this is deemed unnecessary.

[peppy]

This won't immediately be reflected in translations because it's using the same string identifier (and we don't reset existing translations on change to string).

But ignoring that, the problem with saying they are "shared" is the point of question now becomes "so i can't remove stable from my PC after migrating?", as in I don't think this will reduce the support load from this.

[smallketchup82]

This won't immediately be reflected in translations because it's using the same string identifier (and we don't reset existing translations on change to string).

Not a problem, this change isn't as important to need instant updates to translations.

But ignoring that, the problem with saying they are "shared" is the point of question now becomes "so i can't remove stable from my PC after migrating?", as in I don't think this will reduce the support load from this.

Saying the files are "shared" between lazer and stable was honestly the best word I could think of to easily describe to the end user the behaviour of their files after import. I agree it isn't the most accurate wording, but I can't reasonably see users understanding what "hard links" are, nor do I expect them to care enough to find out what they are (via visiting the osu-wiki page on it).

Maybe changing the whole description to something like the following could be better?

Content from an existing osu!(stable) installation can be imported into this installation. If both installations reside on the same drive, content will be linked between installations such that no extra disk space is consumed as a result. Both installations will remain completely independent; removal or modification of one installation will not affect the other. Select the path of your osu!(stable) installation to begin.