Improve file system error feedback

[smg6511]

What does it do?

Creates/updates error messaging to be more accurate and descriptive when a file/folder can not be moved or otherwise changed. Also, in second commit, aligns the code formatting to our current rule set.

Why is it needed?

Current error feedback is for the most part unactionable because it's too ambiguous.

How to test

1. Create at least one file and one folder that have read-only permission.
2. Verify the new messaging appears and its language is clear by attempting to: a) edit (file), rename*, or move a read-only file/directory; or b) create new files/folders in your new read-only directory.

• Note that, interestingly, in many cases renaming or moving a read-only file is possible when you have write permissions on the parent/target directory. This is just how unix works and MODX currently doesn't attempt to apply the fine-grained measures that'd be necessary to lock down files to that degree.

Related issue(s)/PR(s)

Resolves #16074

[codecov]

Codecov Report

Attention: Patch coverage is 22.44898% with 38 lines in your changes are missing coverage. Please review.

Project coverage is 21.57%. Comparing base (f197da7) to head (c7241f2).

Files	Patch %	Lines
core/src/Revolution/Sources/modMediaSource.php	22.44%	38 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##                3.x   #16479   +/-   ##
=========================================
  Coverage     21.57%   21.57%           
- Complexity    10566    10571    +5     
=========================================
  Files           561      561           
  Lines         31940    31966   +26     
=========================================
+ Hits           6892     6898    +6     
- Misses        25048    25068   +20     

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