feat: make it possible to override `method name` in subscriptions (#568)

* feat: override `method` subscription notif

* Arrow syntax for overwrites (#569)

* check that unique notifs are used

* check that custom sub name is unique

* cargo fmt

* address grumbles

* Update proc-macros/src/rpc_macro.rs

* commit added tests

* Update proc-macros/src/render_server.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/render_server.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/rpc_macro.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/rpc_macro.rs

Co-authored-by: David <[email protected]>

* Update utils/src/server/rpc_module.rs

Co-authored-by: David <[email protected]>

* grumbles

* fix long lines

* Update utils/src/server/rpc_module.rs

Co-authored-by: David <[email protected]>

* Update utils/src/server/rpc_module.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/rpc_macro.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/render_server.rs

Co-authored-by: David <[email protected]>

* Update proc-macros/src/render_server.rs

Co-authored-by: David <[email protected]>

* more grumbles

Co-authored-by: Maciej Hirsz <[email protected]>
Co-authored-by: David <[email protected]>