This PR was squashed before being merged into the 3.4 branch (closes#31266).Discussion----------[Translator] Load plurals from po files properly| Q             | A| ------------- | ---| Branch?       | 3.4| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets |#10152 (comment)| License       | MIT| Doc PR        |Plurals were not handled correctly when loading po files.```msgid "foo"msgid_plural "foos"msgstr[0] "bar"msgstr[1] "bars"```Before, the po entry above was treated as two entries, which doesn't make sense:```'foo' => 'bar''foos' => 'bar|bars'```With this PR, it is treated as one entry:```'foo|foos' => 'bar|bars'```Commits-------6b69a99 [Translator] Load plurals from po files properly

This PR was merged into the 3.4 branch.Discussion----------[Translator] Load plurals from mo files properly| Q             | A| ------------- | ---| Branch?       | 3.4| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets |#10152 (comment)| License       | MIT| Doc PR        |Plurals were not handled correctly when loading mo files.```msgid "foo"msgid_plural "foos"msgstr[0] "bar"msgstr[1] "bars"```Before, the mo entry above was treated as two entries, which doesn't make sense:```'foo' => 'bar''foos' => '{0} bar|{1} bars'```With this PR, it is treated as one entry:```'foo|foos' => 'bar|bars'```This PR does the same as#31266, just for mo files instead of po files. Note, however, that the old behavior differed between po and mo files: `'foos' => 'bar|bars'` for po files and `'foos' => '{0} bar|{1} bars'` for mo files.Commits-------97d28b5 Load plurals from mo files properly

…tadly)This PR was submitted for the master branch but it was squashed and merged into the 4.4 branch instead (closes#31269).Discussion----------[Translator] Dump native plural formats to po files| Q             | A| ------------- | ---| Branch?       | master| Bug fix?      | no| New feature?  | yes| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets |#29963,#10152| License       | MIT| Doc PR        |Implementing support for dumping to the native po plural format.```'foo|foos' => 'bar|bars'```Before, the entry above was dumped directly:```msgid "foo|foos"msgstr "bar|bars"```With this PR, it is dumped using the native po plural format:```msgid "foo"msgid_plural "foos"msgstr[0] "bar"msgstr[1] "bars"```Strings using explicit rules or contain more than 2 pluralization forms are still dumped directly, as the po format does not support such cases:```'{0} no foos|one foo|%count% foos' => '{0} no bars|one bar|%count% bars'``````msgid "{0} no foos|one foo|%count% foos"msgstr "{0} no bars|one bar|%count% bars"```This PR complements#31266, fixing loading of native po plural formats.Commits-------dc31739 [Translator] Dump native plural formats to po files