Mandatory `=` sign after message identifier

Fluent
#1

Hi all,

I submitted a proposal to remove the requirement for the mandatory = sign after message identifier in scenarios where the message has no value (just attributes).

The proposed change would allow to write this:

message-key =
    .title = Attribute Value
    .tooltip = Attribute 2 Value

as:

message-key
    .title = Attribute Value
    .tooltip = Attribute 2 Value

This proposal is not directly linked to 0.8 release, and we may consider resolving it even after 1.0, but we would like to collect feedback on it and use it to evaluate the timeline for it.

What do you think?