Add goto-harness man page

[tautschnig]

This was built using help2man and then manually expanded. In the process
of preparing it, several errors in existing goto-harness documentation
were found and fixed as well.

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #6952 (28369a3) into develop (b5ab3a1) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

❗ Current head 28369a3 differs from pull request most recent head f239925. Consider uploading reports for the commit f239925 to get more accurate results

@@             Coverage Diff             @@
##           develop    #6952      +/-   ##
===========================================
- Coverage    77.79%   77.79%   -0.01%     
===========================================
  Files         1568     1568              
  Lines       180347   180329      -18     
===========================================
- Hits        140309   140290      -19     
- Misses       40038    40039       +1     

Impacted Files	Coverage Δ
...goto-harness/memory_snapshot_harness_generator.cpp	76.17% <0.00%> (ø)
src/solvers/smt2/smt2_dec.cpp	71.17% <0.00%> (-2.11%)	⬇️
src/solvers/smt2/smt2_conv.cpp	67.76% <0.00%> (-0.14%)	⬇️
unit/solvers/smt2/smt2_conv.cpp	100.00% <0.00%> (ø)
src/solvers/smt2/smt2_tokenizer.h	96.96% <0.00%> (ø)
...it/solvers/smt2_incremental/smt_to_smt2_string.cpp	100.00% <0.00%> (ø)

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[peterschrammel]

For some reason Github thinks .1 files are not part of the diff and refuses inline comments.
First,function-call -> First, function-call
initialise 🇺🇸