w: delete unnecessary main.rs

[cakebaker]

Currently, there are two main.rs files: one in src/uu/w and the other in src/uu/w/src. The first looks like it's a left-over and so this PR deletes it.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 49.00%. Comparing base (c0386f1) to head (57d801c).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##            main      #76       +/-   ##
==========================================
+ Coverage   0.10%   49.00%   +48.89%     
==========================================
  Files         18       18               
  Lines       1830     2216      +386     
  Branches     239      309       +70     
==========================================
+ Hits           2     1086     +1084     
+ Misses      1827     1082      -745     
- Partials       1       48       +47     

Flag	Coverage Δ
macos_latest	48.37% <ø> (?)
ubuntu_latest	43.97% <ø> (?)
windows_latest	0.10% <ø> (-0.01%)	⬇️

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