Add doc-comment attribute support for typegen outputs

[nedsalk]

forc build adds doc-comment attributes to the generated abi whenever a function has doc comments on it. We can add those comments on typegen-generated functions in the form of multi-line comments.

Below is an example of a sway contract function and its related abi.

    /// Verifies that a newly deployed contract is the child of a contract factory and registers it.
    ///
    /// # Additional Information
    ///
    /// This example does not check whether a contract has already been registered and will overwrite any values.
    ///
    /// # Arguments
    ///
    /// * `child_contract`: [ContractId] - The deployed factory child contract of which to verify the bytecode root.
    /// * `configurables`: [Option<ContractConfigurables>] - The configurables value set for the `child_contract`.
    ///
    /// # Returns
    ///
    /// * [Result<BytecodeRoot, str>] - Either the bytecode root of the newly registered contract or a `str` error message.
    ///
    /// # Number of Storage Accesses
    ///
    /// * Writes: `2`
    ///
    /// # Examples
    ///
    /// ```sway
    /// use src12::SRC12;
    ///
    /// fn foo(my_src_12_contract: ContractId, my_deployed_contract: ContractId, my_configurables: Option<ContractConfigurables>) {
    ///     let src_12_contract_abi = abi(SRC12, my_src_12_contract.bits());
    ///     src_12_contract_abi.register_contract(my_deployed_contract, my_configurables);
    ///     assert(src_12_contract_abi.is_valid(my_deployed_contract));
    /// }
    /// ```
    #[storage(read, write)]
    fn register_contract(
        child_contract: ContractId,
        configurables: Option<ContractConfigurables>,
    ) -> Result<BytecodeRoot, str> { ...

The generated abi will be:

{
      "inputs": [
        {
          "name": "child_contract",
          "type": 10,
          "typeArguments": null
        },
        {
          "name": "configurables",
          "type": 4,
          "typeArguments": [
            {
              "name": "",
              "type": 13,
              "typeArguments": null
            }
          ]
        }
      ],
      "name": "register_contract",
      "output": {
        "name": "",
        "type": 5,
        "typeArguments": [
          {
            "name": "",
            "type": 2,
            "typeArguments": null
          },
          {
            "name": "",
            "type": 9,
            "typeArguments": null
          }
        ]
      },
      "attributes": [
        {
          "name": "doc-comment",
          "arguments": [
            " Verifies that a newly deployed contract is the child of a contract factory and registers it."
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " # Additional Information"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " This example does not check whether a contract has already been registered and will overwrite any values."
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " # Arguments"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " * `child_contract`: [ContractId] - The deployed factory child contract of which to verify the bytecode root."
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " * `configurables`: [Option<ContractConfigurables>] - The configurables value set for the `child_contract`."
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " # Returns"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " * [Result<BytecodeRoot, str>] - Either the bytecode root of the newly registered contract or a `str` error message."
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " # Number of Storage Accesses"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " * Writes: `2`"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " # Examples"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " ```sway"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " use src12::SRC12;"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            ""
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " fn foo(my_src_12_contract: ContractId, my_deployed_contract: ContractId, my_configurables: Option<ContractConfigurables>) {"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            "     let src_12_contract_abi = abi(SRC12, my_src_12_contract.bits());"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            "     src_12_contract_abi.register_contract(my_deployed_contract, my_configurables);"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            "     assert(src_12_contract_abi.is_valid(my_deployed_contract));"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " }"
          ]
        },
        {
          "name": "doc-comment",
          "arguments": [
            " ```"
          ]
        },
        {
          "name": "storage",
          "arguments": [
            "read",
            "write"
          ]
        }
      ]
    }