feat(docs): rewrote the method ID section to remove logical jumps and…

… make it more streamlined

docs/src/content/docs/book/functions.mdx

@@ -315,36 +315,34 @@ contract Treasure {
 
 <Badge text="Available since Tact 1.6" variant="tip" size="medium"/><p/>
 
-As other functions in TVM contracts, getters have their *unique* associated function selectors which are some integers ids (called *method IDs*).
-Some of those integers are reserved for internal purposes, e.g. -4, -3, -2, -1, 0 are reserved IDs and 
-regular functions (internal to a contract and not callable from outside) are usually numbered by subsequent (small) integers starting from 1.
-By default, getters have associated method IDs that are derived from their names using the [CRC16](https://en.wikipedia.org/wiki/Cyclic_redundancy_check) algorithm as follows:
-`crc16(<function_name>) & 0xffff) | 0x10000`.
-Sometimes this can get you the same method ID for getters with different names.
-If this happens, you can either rename some of the contract's getters or
-specify the getter's method ID manually as a compile-time expression like so:
+Like other functions in TON contracts, getters have their _unique_ associated function selectors, which are $19$-bit signed integer identifiers commonly called _method IDs_.
+
+Method IDs of getters are derived from their names using the [CRC16](https://en.wikipedia.org/wiki/Cyclic_redundancy_check) algorithm as follows: `(crc16(<function_name>) & 0xffff) | 0x10000`. In addition, Tact compiler conditionally reserves some method IDs for use in [getters of supported interfaces](/book/contracts#interfaces), namely: $113617$ for `supported_interfaces`, $115390$ for `lazy_deployment_completed`, and $121275$ for `get_abi_ipfs`.
+
+Sometimes, getters with different names end up with the same method ID. If this happens, you can either rename some of the getters or manually specify the method ID as a [compile-time](/ref/core-comptime) expression like so:
 
 ```tact
 contract ManualMethodId {
     const methodId: Int = 16384 + 42;
 
-    get(self.methodId) fun methodId1(): Int {
+    get(self.methodId)
+    fun methodId1(): Int {
         return self.methodId;
     }
 
     get(crc32("crc32") + 42 & 0x3ffff | 0x4000)
     fun methodId2(): Int {
-        return 0;
+        return crc32("crc32") + 42 & 0x3ffff | 0x4000;
     }
 }
 ```
 
-Note that you *cannot* use method IDs that are reserved by TVM and you cannot use some initial positive integers because those will be used as function selectors by the compiler.
+Unlike getters, method IDs for [internal functions](/book/contracts#internal-functions) and some special functions are obtained sequentially: integers in the inclusive range from $-4$ to $0$ are given to [certain message handlers](https://docs.ton.org/v3/documentation/smart-contracts/func/docs/functions#special-function-names), while internal functions are numbered with method IDs starting at $1$ and going up to $2^{14} - 1$ inclusive.
+
+Since method IDs are $19$-bit signed integers and some of them are reserved, only the inclusive ranges from $-2^{18}$ to $-5$ and from $2^{14}$ to $2^{18} - 1$ are free to be used by users. To avoid collisions, it's recommended to specify method IDs only in these ranges, avoiding the method IDs of Tact-specific getters mentioned above.
 
-User-specified method IDs are 19-bit signed integers, so you can use integers from $-2^{18}$ to $-5$ and from $2^{14}$ to $2^{18} - 1$.
 [slice]: /book/cells#slices
 
-Also, a few method IDs are reserved for the usage by the getters the Tact compiler can insert during compilation, those are 113617, 115390, 121275.
 [tvm]: https://docs.ton.org/learn/tvm-instructions/tvm-overview
 [tvm-instructions]: https://docs.ton.org/v3/documentation/tvm/instructions
 [fift]: https://docs.ton.org/v3/documentation/smart-contracts/fift/overview