docs: debugger breakpoints (#884)

* documenting breakpoints

* wrong link and add help

* Update src/forge/debugger.md

---------

Co-authored-by: evalir <[email protected]>

src/SUMMARY.md

@@ -284,6 +284,7 @@
       - [`parseBool`](./cheatcodes/parse-bool.md)
       - [`rememberKey`](./cheatcodes/remember-key.md)
       - [`toString`](./cheatcodes/to-string.md)
+      - [`breakpoint`](./cheatcodes/breakpoint.md)
     - [Snapshots](./cheatcodes/snapshots.md)
     - [RPC](./cheatcodes/rpc.md)
     - [Files](./cheatcodes/fs.md)

src/cheatcodes/breakpoint.md

@@ -0,0 +1,32 @@
+## `breakpoint`
+
+### Signature
+
+```solidity
+function breakpoint(string) external;
+function breakpoint(string, bool) external;
+```
+
+### Description
+
+Places a breakpoint to jump to in the debugger view.
+
+Calling `vm.breakpoint('<char>, true)` is equivalent to `vm.breakpoint('<char>)`, but calling `vm.breakpoint('<char, false)` will erase the breakpoint at `'<char`.
+
+If the char is overwritten, only the last one that was visited in the execution steps is considered.
+
+### Examples
+
+```solidity
+function testBreakpoint() public {
+    vm.breakpoint("a");
+}
+```
+
+Opening up the debugger in a test environment and pressing `'a` will then place the debugger step at the place where the breakpoint cheatcode was called.
+
+![breakpoint a](../images/breakpoint.png)
+
+### SEE ALSO
+
+[debugger](../forge/debugger.md)

src/cheatcodes/utilities.md

@@ -7,3 +7,4 @@
 - [`deriveKey`](./derive-key.md)
 - [`rememberKey`](./remember-key.md)
 - [`toString`](./to-string.md)
+- [`breakpoint`](./breakpoint.md)

src/forge/debugger.md

@@ -62,6 +62,7 @@ For the stack, **cyan words** are either being read or popped by the current opc
 ### General
 
 - <kbd>q</kbd>: Quit the debugger
+- <kbd>h</kbd>: Show help
 
 ### Navigating calls
 
@@ -73,6 +74,7 @@ For the stack, **cyan words** are either being read or popped by the current opc
 - <kbd>C</kbd>: Move to the next call-type instruction
 - <kbd>a</kbd>: Move to the previous [`JUMP`][op-jump] or [`JUMPI`][op-jumpi] instruction
 - <kbd>s</kbd>: Move to the next [`JUMPDEST`][op-jumpdest] instruction
+- <kbd>'</kbd> + <kbd>a-z</kbd>: Move to `<char>` breakpoint set by a [`vm.breakpoint`][cheat-breakpoint] cheatcode
 
 ### Navigating memory
 
@@ -93,3 +95,4 @@ For the stack, **cyan words** are either being read or popped by the current opc
 [op-jumpdest]: https://www.evm.codes/#5b
 [op-jump]: https://www.evm.codes/#f1
 [op-jumpi]: https://www.evm.codes/#57
+[cheat-breakpoint]: ../cheatcodes/breakpoint.md