doc: update memory management info

Author: medvednikov

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## V 0.3.5
 *not yet released*
+- A new VPM site: vpm.vlang.io. A better design, discoverability of packages, descriptions, most downloaded packages etc.
 - Struct fields can now be skipped during JSON/ORM serialization via `[json:'-']` and `[sql:'-']`,
  in addition to `[skip]`. This allows having custom behavior for different serialization methods.
 - ORM: fixed a foreign key bug that could result in an extra insert.
@@ -8,6 +9,7 @@
 - json: Enum value string serialization supports `[json:'alias']` to change its string values.
 - Functions can now return fixed size arrays.
 - The builtin websocket library is now thread safe.
+- Enhanced builtin csrf protection in vweb.
 
 ## V 0.3.4
 

doc/docs.md

@@ -4532,13 +4532,20 @@ fn test_subtest() {
 V avoids doing unnecessary allocations in the first place by using value types,
 string buffers, promoting a simple abstraction-free code style.
 
-Most objects (~90-100%) are freed by V's autofree engine: the compiler inserts
-necessary free calls automatically during compilation. Remaining small percentage
-of objects is freed via reference counting.
+There are 4 ways to manage memory in V.
 
-The developer doesn't need to change anything in their code. "It just works", like in
-Python, Go, or Java, except there's no heavy GC tracing everything or expensive RC for
-each object.
+The default is a minimal and a well performing tracing GC.
+
+The second way is autofree, it can be enabled with `-autofree`. It takes care of most objects
+(~90-100%): the compiler inserts necessary free calls automatically during compilation.
+Remaining small percentage of objects is freed via GC. The developer doesn't need to change
+anything in their code. "It just works", like in Python, Go, or Java, except there's no
+heavy GC tracing everything or expensive RC for each object.
+
+For developers willing to have more low level control, memory can be managed manually with
+`-gc none`.
+
+Arena allocation is available via v `-prealloc`.
 
 ### Control