lang, docs: Remove associated documentation (#506)

docs/src/.vuepress/config.js

@@ -65,7 +65,6 @@ module.exports = {
           "/tutorials/tutorial-3",
           "/tutorials/tutorial-4",
           "/tutorials/tutorial-5",
-          "/tutorials/tutorial-6",
         ],
       },
       {

lang/derive/accounts/src/lib.rs

@@ -49,7 +49,6 @@ use syn::parse_macro_input;
 /// | `#[account(executable)]` | On `AccountInfo` structs | Checks the given account is an executable program. |
 /// | `#[account(state = <target>)]` | On `CpiState` structs | Checks the given state is the canonical state account for the target program. |
 /// | `#[account(owner = <target>)]` | On `CpiState`, `CpiAccount`, and `AccountInfo` | Checks the account owner matches the target. |
-/// | `#[account(associated = <target>, with? = <target>, payer? = <target>, space? = "<literal>")]` | On `ProgramAccount` | Whe `init` is provided, creates an associated program account at a program derived address. `associated` is the SOL address to create the account for. `with` is an optional association, for example, a `Mint` account in the SPL token program. `payer` is an optional account to pay for the account creation, defaulting to the `associated` target if none is given. `space` is an optional literal specifying how large the account is, defaulting to the account's serialized `Default::default` size (+ 8 for the account discriminator) if none is given. When creating an associated account, a `rent` `Sysvar` and `system_program` `AccountInfo` must be present in the `Accounts` struct. When `init` is not provided, then ensures the given associated account has the expected address, defined by the program and the given seeds. |
 // TODO: How do we make the markdown render correctly without putting everything
 //       on absurdly long lines?
 #[proc_macro_derive(Accounts, attributes(account, instruction))]