doc: improve docs for Type and FromRow derives

sqlx-core/src/from_row.rs

@@ -47,6 +47,25 @@ use crate::row::Row;
 ///
 /// will read the content of the column `description` into the field `about_me`.
 ///
+/// #### `rename_all`
+/// By default, field names are expected verbatim (with the exception of the raw identifier prefix `r#`, if present).
+/// Placed at the struct level, this attribute changes how the field name is mapped to its SQL column name:
+///
+/// ```rust,ignore
+/// #[derive(sqlx::FromRow)]
+/// #[sqlx(rename_all = "camelCase")]
+/// struct UserPost {
+///     id: i32,
+///     // remapped to "userId"
+///     user_id: i32,
+///     contents: String
+/// }
+/// ```
+///
+/// The supported values are `snake_case` (available if you have non-snake-case field names for some
+/// reason), `lowercase`, `UPPERCASE`, `camelCase`, `SCREAMING_SNAKE_CASE` and `kebab-case`.
+/// The styling of each option is intended to be an example of its behavior.
+///
 /// #### `default`
 ///
 /// When your struct contains a field that is not present in your query,

sqlx-core/src/types/mod.rs

@@ -98,6 +98,14 @@ pub use json::Json;
 /// struct UserId(i64);
 /// ```
 ///
+/// ##### Attributes
+///
+/// * `#[sqlx(rename = "<SQL type name>")]` on struct definition: instead of inferring the SQL type name from the inner
+/// field (in the above case, `BIGINT`), explicitly set it to `<SQL type name>` instead. May trigger
+/// errors or unexpected behavior if the encoding of the given type is different than that of the
+/// inferred type (e.g. if you rename the above to `VARCHAR`).
+/// Affects Postgres only.
+///
 /// ### Enumeration
 ///
 /// Enumerations may be defined in Rust and can match SQL by