CC Language Ref Polishings (#23762)

Continuation of #23709

- [ ] Add material on how to use the capture checker (wait for cc-lib
merge)
 - [ ] Check everything for completeness and accuracy
- [ ] Also: Add two test files named `reference-cc.scala` in neg and pos
that let us try out the code on the doc pages.

Author: odersky

docs/_docs/reference/experimental/capture-checking/how-to-use.md

@@ -14,6 +14,4 @@ The following options are relevant for capture checking.
 
  - **-Vprint:cc** Prints the program with capturing types as inferred by capture checking.
  - **-Ycc-verbose** Prints capabilities and capturing types in more detail.
- - **-Ycc-debug** Gives more detailed, implementation-oriented information about capture checking, as described in the next section.
-
- The implementation supporting capture checking with these options is currently in branch `cc-experiment` on dotty.epfl.ch.
+ - **-Ycc-debug** Gives more detailed, implementation-oriented information about capture checking, as described in the next section.

docs/_docs/reference/experimental/capture-checking/separation-checking.md

@@ -45,7 +45,7 @@ So, effectively, anything that can be updated must be unaliased.
 ## Capability Kinds
 
 A capability is called
-  - _shared_ if it is [classified](../classifiers.md) as a `SharedCapability`
+  - _shared_ if it is [classified](classifiers.md) as a `SharedCapability`
   - _exclusive_ otherwise.
 
 ## The Mutable Trait
@@ -54,7 +54,7 @@ We introduce a new trait
 ```scala
 trait Mutable extends ExclusiveCapability, Classifier
 ```
-It is used as a [classifier](../classifiers.md) trait for types that define _update methods_ using
+It is used as a [classifier](classifiers.md) trait for types that define _update methods_ using
 a new soft modifier `update`.
 
 **Example:**