rage: Detect PowerShell corruption during decryption

[str4d]

This matches the detection done by age.

Closes #287.

[codecov]

Codecov Report

Merging #301 (01c0519) into main (587fe00) will increase coverage by 0.04%.
The diff coverage is 0.00%.

❗ Current head 01c0519 differs from pull request most recent head 0f04922. Consider uploading reports for the commit 0f04922 to get more accurate results

@@            Coverage Diff             @@
##             main     #301      +/-   ##
==========================================
+ Coverage   37.63%   37.67%   +0.04%     
==========================================
  Files          33       33              
  Lines        2806     2803       -3     
==========================================
  Hits         1056     1056              
+ Misses       1750     1747       -3     

Impacted Files	Coverage Δ
rage/src/bin/rage/main.rs	0.00% <0.00%> (ø)

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