add emphasis in spots

Author: ashnazg

proposed/clock-meta.md

@@ -141,24 +141,24 @@ _**Note:** Order descending chronologically._
 
 There are different reasons why this interface does not enforce a specific timezone.
 
-A purely technical reason is that the interface itself provides an explicit contract. Part of this contract
-is the value returned by the `now()` method. At the language level, the only thing we can enforce is that
+A purely _technical_ reason is that the interface itself provides an explicit contract. Part of this contract
+is the value returned by the `now()` method. At the _language_ level, the only thing we can enforce is that
 the returned value is of type `\DateTimeImmutable`. There is no way to enforce a certain timezone at the
 language level.
 
-A logical reason is that the explicit contract should be usable in all situations where one needs a way to
-retrieve the current time. We should not make an assumption at the contract level about what the caller
+A _logical_ reason is that the explicit contract should be usable in all situations where one needs a way to
+retrieve the current time. We should not make an assumption at the _contract_ level about what the caller
 needs. If the contract did define that only `UTC` is returned, then use cases that require something else
-will have to explicitly work around the returned `UTC` timezone. This is different from issues such as
-immutability, which also cannot be enforced on the language level, but which is still necessary to
-adhere to other calls on the contract.  For this `ClockInterface`, there will be no other calls.
+would have to explicitly work around the returned `UTC` timezone. This is different from issues such as
+immutability, which also cannot be enforced on the language level, but which is still necessary to adhere
+to other calls on the contract.  For this `ClockInterface`, there will be no other calls.
 
-Most importantly, the explicit contract provided by this interface does not prevent a user from using
+Most importantly, the explicit contract provided by this interface does not _prevent_ a user from using
 an implicit contract alongside logic to return a `\DateTimeImmutable` with a specific timezone. Whether
-that is `UTC` or `Antarctica/Troll`, it is the user who is in control of this.
+that is `UTC` or `Antarctica/Troll`, it is the _user_ who is in control of this.
 
 The explicit contract defined by the interface does not limit a user in what they are doing. It tries to
 solve the problem of getting the current time in a reliable way. Whatever view on the current time that is,
 it is not part of the explicit contract.
 
-Thus, this interface tries to be as open as possible, while at the same time, being as strict as necessary.
+Thus, this interface tries to be as _open as possible_, while at the same time, being as _strict as necessary_.