Show warning if slash is entered as filename

[MorrisJobke]

Fixes#6594 when creating or renaming a file.

[MariusBluem]

For now, fine 😉 But what do you think about creating a directory with that file when somebody types in "testfolder/testdoc.docx" as document name 🤔 @MorrisJobke

[MorrisJobke]

For now, fine 😉 But what do you think about creating a directory with that file when somebody types in "testfolder/testdoc.docx" as document name 🤔 @MorrisJobke

Something for later and also a bit over the top from my point of view.

[codecov]

Codecov Report

Merging #7676 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@ Coverage Diff @@## master #7676 +/- ##
===========================================
+ Coverage 51.19% 51.2% +0.01% - Complexity 24888 24893 +5 
===========================================
Files 1601 1602 +1 Lines 94781 94803 +22 Branches 1371 1372 +1 ===========================================
+ Hits 48523 48544 +21 - Misses 46258 46259 +1

Impacted Files	Coverage Δ	Complexity Δ
.../dav/lib/Connector/Sabre/ExceptionLoggerPlugin.php	78.94% <ø> (ø)	6 <0> (ø)	⬇️
lib/private/Files/Cache/Propagator.php	94.93% <0%> (-1.27%)	16% <0%> (ø)
core/js/js.js	65.88% <0%> (ø)	0% <0%> (ø)	⬇️
lib/private/Template/JSConfigHelper.php	0% <0%> (ø)	18% <0%> (+1%)	⬆️
...leware/Security/PasswordConfirmationMiddleware.php	82.35% <0%> (ø)	6% <0%> (?)
...e/AppFramework/DependencyInjection/DIContainer.php	78.6% <0%> (+0.77%)	27% <0%> (ø)	⬇️
apps/files_trashbin/lib/Expiration.php	91.93% <0%> (+1.61%)	29% <0%> (ø)	⬇️
...amework/Middleware/Security/SecurityMiddleware.php	80.26% <0%> (+2.48%)	25% <0%> (-2%)	⬇️
...ware/Security/Exceptions/NotConfirmedException.php	100% <0%> (+100%)	1% <0%> (ø)	⬇️

[MorrisJobke]

The second commit fixes all the cases of #6594 (comment) and logs them as debug logs.

[skjnldsv]

Strange it was not already implemented! 🤔