Further Http Headers work

[midgleyc]

• on a pseudo-response, the Date header had the wrong format
• on a pseudo-response, leave it up to the browser as to whether or not to close the connection
• log more information in case of IOException, to try to track down why that happens sometimes

[codecov]

Codecov Report

Merging #663 (6f522da) into main (533ec5c) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##               main     #663      +/-   ##
============================================
- Coverage     21.84%   21.84%   -0.01%     
+ Complexity     9407     9406       -1     
============================================
  Files          1003     1003              
  Lines        157146   157146              
  Branches      34829    34830       +1     
============================================
- Hits          34330    34324       -6     
- Misses       116553   116555       +2     
- Partials       6263     6267       +4     

Impacted Files	Coverage Δ
...t/sourceforge/kolmafia/request/GenericRequest.java	21.37% <0.00%> (-0.05%)	⬇️
...net/sourceforge/kolmafia/request/RelayRequest.java	5.19% <0.00%> (+<0.01%)	⬆️
src/net/sourceforge/kolmafia/webui/RelayAgent.java	0.00% <0.00%> (ø)
...sourceforge/kolmafia/textui/langserver/Script.java	81.91% <0.00%> (-3.20%)	⬇️
src/net/sourceforge/kolmafia/KoLCharacter.java	44.31% <0.00%> (-0.13%)	⬇️
...rceforge/kolmafia/persistence/HolidayDatabase.java	34.57% <0.00%> (ø)

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