[DOCUMENTATION] Add line to show that grpc_server_max_send_msg_size is configurable a…

[thejosephstevens]

…nd add language to explain when you might need to modify it

What this PR does:
I ran into this issue when trying to view a large trace from Loki (25k spans).

I was able to get past the issue by increasing server. grpc_server_max_recv_msg_size from 4194304 to 104857600.

I exchanged messages with @kvrhdn and he pointed out that the ingester_client configured in the querier is instantiated with a message send size much higher than the default message receive max size used by the ingester.
Which issue(s) this PR fixes:
I didn't get all the way to a Github Issue, but I dropped this message in the Tempo slack.

Hey all! I’m running into an issue with Tempo where a query is failing on max grpc message size received. I’m a bit confused because I only see one place in the tempo config to configure grpc max receive message size (in the server block), so I’m not clear on what else could be sending a message that’s too large. I am currently using the default value there of 4194304. Does anyone have pointers for where to look?

Checklist

• (N/A) - Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[CLAassistant]

All committers have signed the CLA.

[KMiller-Grafana]

I approve of the docs change, but wish that you'd add the units to description for both the recv and send message size.

It'd read something like

Max gRPC message size in bytes that can be received

[annanay25]

Oops! I didn't see the comment from Karen. Will add in a follow up PR.