chore: Fix new clippy lint

The new lint that is handled here is
too_long_first_doc_paragraph.

crates/ruma-common/src/serde/raw.rs

@@ -11,9 +11,10 @@ use serde::{
 };
 use serde_json::value::{to_raw_value as to_raw_json_value, RawValue as RawJsonValue};
 
-/// A wrapper around `Box<RawValue>`, to be used in place of any type in the Matrix endpoint
-/// definition to allow request and response types to contain that said type represented by
-/// the generic argument `Ev`.
+/// A wrapper around `Box<RawValue>`.
+///
+/// To be used in place of any type in the Matrix endpoint definition to allow request and response
+/// types to contain that said type represented by the generic argument `Ev`.
 ///
 /// Ruma offers the `Raw` wrapper to enable passing around JSON text that is only partially
 /// validated. This is useful when a client receives events that do not follow the spec perfectly

crates/ruma-common/src/serde/strings.rs

@@ -9,6 +9,7 @@ use serde::{
 
 /// Serde deserialization decorator to map empty Strings to None,
 /// and forward non-empty Strings to the Deserialize implementation for T.
+///
 /// Useful for the typical
 /// "A room with an X event with an absent, null, or empty Y field
 /// should be treated the same as a room with no such event."

crates/ruma-events/src/call/member.rs

@@ -147,7 +147,9 @@ pub struct EmptyMembershipData {
 }
 
 /// This is the optional value for an empty membership event content:
-/// [`CallMemberEventContent::Empty`]. It is used when the user disconnected and a Future ([MSC4140](https://github.com/matrix-org/matrix-spec-proposals/pull/4140))
+/// [`CallMemberEventContent::Empty`].
+///
+/// It is used when the user disconnected and a Future ([MSC4140](https://github.com/matrix-org/matrix-spec-proposals/pull/4140))
 /// was used to update the membership after the client was not reachable anymore.  
 #[derive(Clone, PartialEq, StringEnum)]
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]