Edit type/func documentation in the consumer package

[eddyleelin]

Description:
This PR updates the documentation of type and func declarations in the consumer package and all of its subpackages, with a focus on correcting grammar/spelling mistakes, cleaning up syntax to render the examples better, and updating incorrect references or wording. Note that this does not

Link to tracking Issue:
Addresses part of issue #3050.
Related to #3361

Documentation:

• Add number of upstream PR.

[bogdandrutu]

Tests failed:

make build-binary-internal
make[1]: Entering directory '/home/circleci/project'
GO111MODULE=on CGO_ENABLED=0 go build -trimpath -o ./bin/otelcol_linux_amd64 -ldflags "-X go.opentelemetry.io/collector/internal/version.Version=v0.27.0-33-g84329591" ./cmd/otelcol
# go.opentelemetry.io/collector/consumer/pdata
consumer/pdata/generated_log.go:21:2: imported and not used: "go.opentelemetry.io/collector/internal/data/protogen/common/v1" as otlpcommon
consumer/pdata/generated_trace.go:21:2: imported and not used: "go.opentelemetry.io/collector/internal/data"
consumer/pdata/generated_trace.go:22:2: imported and not used: "go.opentelemetry.io/collector/internal/data/protogen/common/v1" as otlpcommon
make[1]: *** [Makefile:252: build-binary-internal] Error 2
make[1]: Leaving directory '/home/circleci/project'
make: *** [Makefile:163: otelcol] Error 2

[bogdandrutu]

Can you please for me split this into 2 PRs:

1. cmd/pdatagen and consumer/pdata
2. Rest of the files

This will help me a lot for review.

[eddyleelin]

Thanks @bogdandrutu for the suggestion; I have updated this PR to not contain any of the cmd/pdatagen/internal or consumer/pdata/generated*.go files! Those files will be handled in the PR #3361 . Thanks again 😄

[tigrannajaryan]

The reference to "traces" is confusing here. @bogdandrutu do you know what this is supposed to mean?

[tigrannajaryan]

Please resolve the conflicts.

[alolita]

@bogdandrutu can you please review and this PR can then be merged if all is done.