Updated connection reference doco and added missing newline

Author: trueqbit

dev/connection_holder.h

@@ -228,6 +228,8 @@ namespace sqlite_orm {
 
         /*  
             Acquires a database connection upon construction and releases it upon destruction.
+
+            Note: It is important to cache the `sqlite3*` pointer for cache-friendliness (thus avoiding to access the holder on each `get()` call).
          */
         struct connection_ref {
             connection_ref(connection_holder& holder) : holder{&holder}, db{holder.retain()} {}
@@ -259,6 +261,8 @@ namespace sqlite_orm {
 
         /*  
             Increases the reference count of an existing open connection upon construction and releases it upon destruction.
+
+            Note: It is important to cache the `sqlite3*` pointer for cache-friendliness (thus avoiding to access the holder on each `get()` call).
          */
         struct connection_ptr {
             connection_ptr(connection_holder& holder) : holder{&holder}, db{holder.retain_if_open()} {}

dev/functional/cxx_scope_guard.h

@@ -13,4 +13,4 @@ namespace sqlite_orm::internal {
 
         F f;
     };
-}
+}

include/sqlite_orm/sqlite_orm.h

@@ -14514,6 +14514,7 @@ namespace sqlite_orm::internal {
         F f;
     };
 }
+
 // #include "functional/gsl.h"
 
 // #include "error_code.h"
@@ -14851,6 +14852,8 @@ namespace sqlite_orm {
 
         /*  
             Acquires a database connection upon construction and releases it upon destruction.
+
+            Note: It is important to cache the `sqlite3*` pointer for cache-friendliness (thus avoiding to access the holder on each `get()` call).
          */
         struct connection_ref {
             connection_ref(connection_holder& holder) : holder{&holder}, db{holder.retain()} {}
@@ -14882,6 +14885,8 @@ namespace sqlite_orm {
 
         /*  
             Increases the reference count of an existing open connection upon construction and releases it upon destruction.
+
+            Note: It is important to cache the `sqlite3*` pointer for cache-friendliness (thus avoiding to access the holder on each `get()` call).
          */
         struct connection_ptr {
             connection_ptr(connection_holder& holder) : holder{&holder}, db{holder.retain_if_open()} {}