docs: small emulator docs tweaks

Author: msm-code

README.md

@@ -135,7 +135,7 @@ More detailed tutorial about specific features is in development. Completed chap
 
 * [Emulator](https://msm-code.github.io/ghidralib/emulator/)
 
-If you prefer to learn by example, tou can also browse the [examples](./examples/) directory.
+If you prefer to learn by example, you can also browse the [examples](./examples/) directory.
 
 A fair warning: ghidralib is still actively developed and the API may change
 slightly in the future. But this doesn't matter for your one-off scripts, does it?

docs/emulator.md

@@ -32,7 +32,9 @@ void check(int value) {
 }
 
 int main(int argc, char *argv[]) {
+    if (argc != 2) { return 1; }
     check(atoi(argv[1]));
+    return 0;
 }
 ```
 
@@ -274,6 +276,10 @@ emu.add_hook(Symbol("hash").address, hash_hook)
 emu.emulate(Symbol("check").address)
 ```
 
+**Exercise**: Create a hook for `atoi` function that will simulate the libc function -
+it should parse the string from the parameter and return it in RAX. Test it by emulating
+the "call atoi" instruction with a string parameter.
+
 ### State inspection
 
 Of course, after emulation we are interested in the final state of the emulator.
@@ -319,6 +325,10 @@ It doesn't get any easier than that. The `simple` in the name refers to the retu
 in many cases you will want to use `Function.emulate` to get the whole context of the
 emulator after execution.
 
+**Exercise**: Complete the `atoi` hook from the previous exercise first. Then create an emulator,
+add `printf` and `atoi` hooks, and execute a `main` function with the correct parameters.
+This will require you to pass correct `argc` and `argv` parameters.
+
 ### Misc features
 
 **maxsteps**