Suggesstion: Implement `patch` to generate a patch for the suggestion

Still working on it, but have an initial draft working. There's no file
name in the diff hunk, so I'm assuming I'm going to have to add one
later.

Build a patch from the diff hunk and suggestion comment.

1. Remove `-` lines
2. Change `+` lines to ` `
3. Change last line to `-`
4. Append suggestion to the diff with a `+` prefix

1 files changed, 1 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 651abdc..f00d14f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,7 @@ edition = "2018"
 
 [dependencies]
 github-rs = "0.7.0"
+regex = "1.3.9"
 serde = { version = "1.0.114", features = ["derive"] }
 serde_json = "1.0.56"
 thiserror = "1.0.20"