README - errors running verification steps - speccheck, spellcheck

[macfarla]

I tried to follow the instructions on the readme to build/run/verify my changes and got the below errors with speccheck and spellcheck.

➜  execution-apis git:(keys-non-empty) ✗ go install github.com/lightclient/rpctestgen/cmd/speccheck@latest
go: downloading github.com/lightclient/rpctestgen v0.0.0-20250211111348-0463f3abc31a
go: downloading github.com/santhosh-tekuri/jsonschema/v5 v5.0.0
go: downloading github.com/alexflint/go-arg v1.4.3
go: downloading github.com/open-rpc/meta-schema v0.0.0-20210416041958-626a15d0a618
go: downloading github.com/alexflint/go-scalar v1.1.0
➜  execution-apis git:(keys-non-empty) ✗ speccheck -v
zsh: command not found: speccheck

➜  execution-apis git:(keys-non-empty) ✗ pyspelling -c spellcheck.yaml
['aspell', '--lang', 'en', '--encoding', 'utf-8', 'create', 'master', '/Users/sallymacfarlane/workspace/execution-apis/dictionary.dic']
Current wordlist: 'wordlist.txt'
Problem compiling dictionary. Check the binary path and options.
Traceback (most recent call last):
  File "/usr/local/bin/pyspelling", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__main__.py", line 37, in main
    return run(
           ^^^^
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__main__.py", line 64, in run
    for results in spellcheck(
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__init__.py", line 742, in spellcheck
    for result in spelltask.run_task(task, source_patterns=sources):
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__init__.py", line 657, in run_task
    self.personal_dict = self.spellchecker.setup_dictionary(self.task, self.binary, self.verbose)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__init__.py", line 273, in setup_dictionary
    cls.compile_dictionary(
  File "/usr/local/lib/python3.11/site-packages/pyspelling/__init__.py", line 315, in compile_dictionary
    util.call(
  File "/usr/local/lib/python3.11/site-packages/pyspelling/util/__init__.py", line 97, in call
    process = get_process(cmd)
              ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pyspelling/util/__init__.py", line 66, in get_process
    process = subprocess.Popen(
              ^^^^^^^^^^^^^^^^^
  File "/usr/local/Cellar/python@3.11/3.11.11/Frameworks/Python.framework/Versions/3.11/lib/python3.11/subprocess.py", line 1026, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/local/Cellar/python@3.11/3.11.11/Frameworks/Python.framework/Versions/3.11/lib/python3.11/subprocess.py", line 1955, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'aspell'