Updated AddLegacyActivity method name to AddLegacySource

[utpilla]

Changes

• Updated AddLegacyActivity to AddLegacySource

• CHANGELOG.md updated for non-trivial changes
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #1860 (ed4f9cf) into main (cb066cb) will decrease coverage by 0.43%.
The diff coverage is 78.63%.

@@            Coverage Diff             @@
##             main    #1860      +/-   ##
==========================================
- Coverage   83.77%   83.34%   -0.44%     
==========================================
  Files         187      188       +1     
  Lines        5967     6130     +163     
==========================================
+ Hits         4999     5109     +110     
- Misses        968     1021      +53     

Impacted Files	Coverage Δ
src/OpenTelemetry/Sdk.cs	100.00% <ø> (ø)
src/OpenTelemetry/Logs/OpenTelemetryLogger.cs	26.82% <20.54%> (-44.60%)	⬇️
src/OpenTelemetry/Logs/LogRecord.cs	82.50% <77.77%> (-5.00%)	⬇️
.../OpenTelemetry/Logs/OpenTelemetryLoggerProvider.cs	77.55% <88.23%> (+7.09%)	⬆️
src/OpenTelemetry/Trace/ExceptionProcessor.cs	90.90% <90.90%> (ø)
...rc/OpenTelemetry/Trace/TracerProviderBuilderSdk.cs	89.83% <91.66%> (-0.92%)	⬇️
src/OpenTelemetry/Trace/TracerProviderSdk.cs	95.16% <98.64%> (+4.38%)	⬆️
...metryProtocol/Implementation/ActivityExtensions.cs	86.89% <100.00%> (+0.05%)	⬆️
...ry.Instrumentation.AspNet/AspNetInstrumentation.cs	100.00% <100.00%> (ø)
...umentation.AspNet/Implementation/HttpInListener.cs	89.10% <100.00%> (ø)
... and 23 more

[CodeBlanch]

I think the code comments should use a plural tense. Here's an alternative:

        /// <summary>
        /// Adds a listener for <see cref="Activity"/> objects created with the given operation name to the <see cref="TracerProviderBuilder"/>.
        /// </summary>
        /// <remarks>
        /// This is provided to capture legacy <see cref="Activity"/> objects creared without using the <see cref="ActivitySource"/> API.
        /// </remarks>
        /// <param name="tracerProviderBuilder"><see cref="TracerProviderBuilder"/> instance.</param>
        /// <param name="operationName">Operation name of the <see cref="Activity"/> objects to capture.</param>
        /// <returns>Returns <see cref="TracerProviderBuilder"/> for chaining.</returns>
        public static TracerProviderBuilder AddLegacyActivity(this TracerProviderBuilder tracerProviderBuilder, string operationName)

[utpilla]

I have updated the code comments.

[cijothomas]

no need of this. as this was never released.