chore: fixed broken links (#375)

* fixed broken links in riscv `instruction.rs`

* updated formating of link `runtime/README.md`

* Update link `runtime/README.md`

Author: youyyytrok

runtime/README.md

@@ -68,7 +68,7 @@ function directly. The fourth line brings the nexux-rt
 `main` function as the starting point of the program.
 
 To see more, such as how to introduce program i/o, precompiles,
-and native compilation support, check out our [documentation](docs.nexus.xyz).
+and native compilation support, check out our [documentation](https://docs.nexus.xyz/zkvm/index).
 
 ## Crate Overview
 #### Execution flow
@@ -87,4 +87,4 @@ and native compilation support, check out our [documentation](docs.nexus.xyz).
 - `#[nexus_rt::main]` transforms the main body of a rust function to make the development process simpler and more intuitive. In this way, at surface level the main function will take inputs and return outputs as defined in the function signature (Ex: `fn main(x: u32) -> u32`). Under the hood, the guest program I/O memory interactions will happen via `read_public_input`, `read_private_input`, and `write_public_output` in `src/io.rs`.
 - By default all I/O will be treated as public I/O. To create a private input `x`, define the variable in the main function signature, and use the macro `[nexus_rt::private_input(x)]`.
 - The guest program development workflow allows for simultaneous multi-target compatibility. In order for this to work, every input and output variable must have a corresponding native handler (since native running has no concept of guest program memory). The macros for this are `[nexus_rt::custom_input]` and `[nexus_rt::custom_output]`.
-- All of these definitions can be found in `macros/`. For additional examples and understanding, refer to `macros/macro_expansion_tests/tests`. Note that macros expand differently depending on the target (native vs RISC-V).
+- All of these definitions can be found in `macros/`. For additional examples and understanding, refer to `macros/macro_expansion_tests/tests`. Note that macros expand differently depending on the target (native vs RISC-V).

vm/src/riscv/instructions/instruction.rs

@@ -5,9 +5,9 @@
 //! various RISC-V instruction formats.
 //!
 //! References:
-//! - <https://github.com/riscv/riscv-opcodes/blob/master/rv32_i>
-//! - <https://github.com/riscv/riscv-opcodes/blob/master/rv_i>
-//! - <https://github.com/riscv/riscv-opcodes/blob/master/rv_m>
+//! - <https://github.com/riscv/riscv-opcodes/blob/master/extensions/rv32_i>
+//! - <https://github.com/riscv/riscv-opcodes/blob/master/extensions/rv_i>
+//! - <https://github.com/riscv/riscv-opcodes/blob/master/extensions/rv_m>
 
 use crate::riscv::instructions::macros::{
     impl_b_type_instructions, impl_i_type_instructions, impl_i_type_shamt_instructions,