Expand descriptions of LSH-relevant arguments in README and help messages

[haydenm]

This PR expands descriptions of arguments that use locality-sensitive hashing—to lower runtime and memory usage on especially large inputs—in the README and help messages. Namely, the PR:

• Adds technical detail to the arguments in the README, borrowing from the help messages
• Adds detail on why certain values for these arguments are recommended and reasonable in practice
• Makes minor changes to the help messages

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (895a7e3) 93.73% compared to head (d178bd4) 93.73%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #57   +/-   ##
=======================================
  Coverage   93.73%   93.73%           
=======================================
  Files          63       63           
  Lines        6115     6115           
=======================================
  Hits         5732     5732           
  Misses        383      383           

Flag	Coverage Δ
unittests	93.73% <ø> (ø)

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