Update policyfile.md (#4345)

Signed-off-by: Ian Maddaus <[email protected]>

typo

Author: IanMadd

content/policyfile.md

@@ -65,7 +65,7 @@ Policyfile effectively replaces roles and environments. Policyfile files are ver
 
 ### Cookbook Mutability
 
-When running Chef without Policyfile, existing versions of cookbooks are mutable. This is convenient for many use cases, especially if users upload in-development cookbook revisions to the Chef Infra Server. But this sometimes creates issues that are similar to role mutability by allowing those cookbook changes to be applied immediately to nodes that use that cookbook. Users account for this by rigorous testing processes to ensure that only fully integrated cookbooks are ever published. This process does enforce good development habits, but at the same time it should not be a required part of a workflow that ends with publishing an in-development cookbook to the Chef Infra Server for testing against real nodes Policyfile solves this issue by using a cookbook publishing API for the Chef Infra Server that does not provide cookbook mutability. Name collisions are prevented by storing cookbooks by name and an opaque identifier that is computed from the content of the cookbook itself.
+When running Chef without Policyfile, existing versions of cookbooks are mutable. This is convenient for many use cases, especially if users upload in-development cookbook revisions to the Chef Infra Server. But this sometimes creates issues that are similar to role mutability by allowing those cookbook changes to be applied immediately to nodes that use that cookbook. Users account for this by rigorous testing processes to ensure that only fully integrated cookbooks are ever published. This process does enforce good development habits, but at the same time it should not be a required part of a workflow that ends with publishing an in-development cookbook to the Chef Infra Server for testing against real nodes. Policyfile solves this issue by using a cookbook publishing API for the Chef Infra Server that does not provide cookbook mutability. Name collisions are prevented by storing cookbooks by name and an opaque identifier that is computed from the content of the cookbook itself.
 
 For example, name/version collisions can occur when users temporarily fork an upstream cookbook. Even if the user contributes their change and the maintainer is responsive, there may be a period of time where the user needs their fork to make progress. This situation presents a versioning dilemma: if the user does not update their own version, they must overwrite the existing copy of that cookbook on the Chef Infra Server, wheres if they do update the version number it might conflict with the version number of the future release of that upstream cookbook.