fix: Parsers do not have to be in seperate files

[lelandbatey]

On the "Configuring parsers" section, subsection "Parser Configuration File"[2], it says:

All parsers must be defined in a parsers file, not in the Fluent Bit
global configuration file.

But on the "Parsers" page[1] for the v4.0 documentation, it states:

You can define parsers either directly in the main configuration file
or in separate external files for better organization.

Those seem like contradictory statements. I think the truth is that parsers may be defined in the main global configuration file if the main configuration file is YAML, or in a separate "parsers" file in either classic or YAML config files. I think the behavior of supporting parsers defined in the main YAML configuration file has been supported since v3.2

I'm proposing the smallest possible change to make the docs no longer be incorrect, but please close this PR if y'all feel there's broader changes to be made to these docs.

[1] - https://docs.fluentbit.io/manual/administration/configuring-fluent-bit/yaml/parsers-section
[2] - https://docs.fluentbit.io/manual/data-pipeline/parsers/configuring-parser#parsers-configuration-file

[patrick-stephens]

I don't think Parsers can be defined in the main configuration file unless it is YAML format, this is likely where the confusion came from with updates recently to add all the YAML docs in.

Additionally you can define in YAML or legacy format in separate files then reference them in the main configuration file in either format, e.g. you can have a YAML main config file using legacy format parser files which is useful for moving to the new YAML format.

[esmerel]

Oof, thanks for catching that - I'll try to come back to this later in the week to clarify this so to be more correct for the specific situations.

[lelandbatey]

@esmerel @patrick-stephens Thank you for the changes, and thank you for your work on Fluentbit!