Make the 'Pin to Dock' label translatable

[xalt7x]

With the single underscore (_) we can re-use original translation.
However, for the 'Pin to Dock' there's no match since GNOME 42-47 original label is 'Pin to Dash'.
Using two underscores (__) as a translation function resolves #2330

[xalt7x]

See also:

• Change "Show Details" to GNOME's "App Details" #2117
• GNOME commit "dash: Use pin instead of favorites"
• commit "appIcons: Drop code that is not used anymore by any supported version"
• commit "Fix translation of popupmenu strings (e.g. "All Windows")."

[sergio-costas]

In my opinion, this should be fixed by updating the translations, not by reusing the translation of a different text.

[xalt7x]

@sergio-costas

In my opinion, this should be fixed by updating the translations, not by reusing the translation of a different text.

I've actually tried updating translation file (before making comparison screenshots I've modified uk_UA.po). Still, my translation of 'Pin to Dock' was unused until I've applied a change from this PR. Please see issue #2104 that confirms that translation updates won't help here.

With the current
const item = this._appendMenuItem(_('Pin to Dock'));
This extension tries to re-use GNOME string. However, Pin to Dock string doesn't exist in GNOME Dash so we receive English/untranslated item.

One can simply try to re-use GNOME Dash string 'Pin to Dash'.
const item = this._appendMenuItem(_('Pin to Dash'));
Now, an item uses GNOME translation but this hacky solution is bad for multiple reasons:

• Dash to Dock pot file will contain 'Pin to Dash' instead of 'Pin to Dock'.
• Translators would need to update .po files and translate 'Dash' as 'Dock'. For that, they would need to have knowledge for meaning of the hack, existence of the issue "Pin To Dock" menu item is untranslatable #2330 and discussion in this PR.

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With the simple fix I propose
const item = this._appendMenuItem(__('Pin to Dock'));
Pin to Dock translation will be used after .po file updates.

I believe this is the right way.