Add span status and error recording subsections to trace docs

[cartermp]

For some reason I thought the docs had these, but someone brought it up in a support forum and they couldn't find where to record an error. This should bring the manual tracing docs more up to par with other languages that document this.

[codecov]

Codecov Report

Merging #2893 (2209f1b) into main (a0bed80) will increase coverage by 0.0%.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main   #2893   +/-   ##
=====================================
  Coverage   75.7%   75.7%           
=====================================
  Files        177     177           
  Lines      11819   11819           
=====================================
+ Hits        8950    8954    +4     
+ Misses      2636    2632    -4     
  Partials     233     233           

Impacted Files	Coverage Δ
sdk/trace/batch_span_processor.go	82.1% <0.0%> (+1.8%)	⬆️

[XSAM]

lgtm

[benjaminclauss]

By default, the status for all spans is Unset. In rare cases, you may also wish to set the status to Ok. This should generally not be necessary, though.

What are "rare cases"?
It seems odd that the documentation advises setting a status for error cases but leaving it unset otherwise.

[benjaminclauss]

https://opentelemetry.io/docs/instrumentation/go/getting-started/

1. setting the status before recording an error - This differs from the "Getting Started" documentation.
2. Similarly, why use "operationThatCouldFail failed" for the description as opposed to err.Error(). Is there a best practice?

[MrAlias]

By default, the status for all spans is Unset. In rare cases, you may also wish to set the status to Ok. This should generally not be necessary, though.

What are "rare cases"? It seems odd that the documentation advises setting a status for error cases but leaving it unset otherwise.

Please open a new issue or discussion to address any new questions you have instead of commenting here.

[benjaminclauss]

opened #2943