Let ai.scriptget and ai.modelget commands run successfully without optional args

[alonre24]

Align script get and model get command, so it will return both source/blob and meta if no optional argument is specified.
This PR also contains some documentation corrections for the new script commands.

[codecov]

Codecov Report

Merging #791 (81b528b) into master (d74d953) will increase coverage by 0.06%.
The diff coverage is 96.00%.

@@            Coverage Diff             @@
##           master     #791      +/-   ##
==========================================
+ Coverage   79.95%   80.01%   +0.06%     
==========================================
  Files          53       53              
  Lines        8037     8032       -5     
==========================================
+ Hits         6426     6427       +1     
+ Misses       1611     1605       -6     

Impacted Files	Coverage Δ
src/redisai.c	86.99% <96.00%> (+1.07%)	⬆️
...c/serialization/RDB/decoder/current/v3/decode_v3.c	65.38% <0.00%> (-2.75%)	⬇️
src/backends/onnxruntime.c	77.88% <0.00%> (+0.50%)	⬆️

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[DvirDukhan]

please add comments to the if confitions or have some kind of format enumt