Fix SDLFileManager Typo

[theresalech]

Fixes #2073

Risk

This PR makes no API changes.

Testing Plan

• I have verified that I have not introduced new warnings in this PR (or explain why below)
• I have run the unit tests with this PR
• I have tested this PR against Core and verified behavior (if applicable, if not applicable, explain why below).

The above are not needed as the PR only fixes a typo in an SDLFileManager description.

Summary

Fix typo described in #2073

CLA

• I have signed the CLA

[codecov]

Codecov Report

Merging #2074 (ab16ac4) into develop (bd8041d) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #2074      +/-   ##
===========================================
- Coverage    85.83%   85.81%   -0.03%     
===========================================
  Files          447      447              
  Lines        23392    23393       +1     
===========================================
- Hits         20079    20075       -4     
- Misses        3313     3318       +5