Improve wording in error handling guide
Improve wording in error handling guide

The original blog post referred to examples by their file names, and now
that it's in guide form, there is no file name. So edit the text so that
it makes a bit more sense.

Fixes #28428

GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,graydon/rust,graydon/rust