Mutex blog post

I enjoyed the Mutex blog post - nice to see STM being brought to a wider audience :)

Some typos I noticed -

- https://github.com/ChrisPenner/ChrisPenner.github.io/blob/2c4f0c0b923e03eba38059ec798d97d6d1730eb4/site/posts/mutexes.md?plain=1#L183

"money will been withdrawn" should be "money will *have* been withdrawn"

- https://github.com/ChrisPenner/ChrisPenner.github.io/blob/2c4f0c0b923e03eba38059ec798d97d6d1730eb4/site/posts/mutexes.md?plain=1#L353

"swath" should probably be "swath of"

- https://github.com/ChrisPenner/ChrisPenner.github.io/blob/2c4f0c0b923e03eba38059ec798d97d6d1730eb4/site/posts/mutexes.md?plain=1#L388

?? possibly "did I mention *they*" should be "did I mention *it*" - if STM is being referred to. But if "abstractions" are being referred to, it's all fine.

- https://github.com/ChrisPenner/ChrisPenner.github.io/blob/2c4f0c0b923e03eba38059ec798d97d6d1730eb4/site/posts/mutexes.md?plain=1#L455

"`balaceVar`" should be "`balanceVar`"

- https://github.com/ChrisPenner/ChrisPenner.github.io/blob/2c4f0c0b923e03eba38059ec798d97d6d1730eb4/site/posts/mutexes.md?plain=1#L514

Unbalanced parens - needs a "`)`" at the end of the line.

Cheers!