[String] do not add an extra s at the end if last character is s

[k0d3r1s]

Q	A
Branch?	5.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Issues	Fix #52800
License	MIT

As already written in #52800, settings, for example, already end with s, so assumption to add extra s at the end is incorrect

[OskarStark]

Can you please add a test case to avoid further regressions? Thank you

[acirulis]

How about words, such as :
Corps -> corps
Diagnosis -> diagnoses
Ethos -> ethe or ethea or ethoses
Gas -> gases

Current output of Inflector is as follows:

Corpss
Diagnoses # only one correct
Ethoss
Gass

[k0d3r1s]

@OskarStark added tests

+ extra words from comments

[derrabus]

The inflector is meant to pluralize singular terms. That's its purpose. If the term in question is already a plural, you should not use it. And neither is this class meant to detect or normalize plural forms.

[acirulis]

@derrabus maybe so but this issue started when Api Platform switched from doctrine/inflector (which does check if plural form is already used) to symfony/string (not sure the reasoning). Please see api-platform/core#5957

[fiburonsk]

I came across alias it should be aliases but the EnglishInflector generates aliass instead, similar to gas and gases above.