Clean up some newly added userdocs

Author: bnbarham

userdocs/diagnostics/compilation-caching.md

@@ -1,4 +1,9 @@
-# Compilation Caching
+# Compilation caching (CompilationCaching)
+
+Errors and warnings related to the compiler's CAS compilation caching.
+
+
+## Overview
 
 Compilation caching allows Swift compiler to reuse previously compiled outputs if the identical
 compilation has been done before.

userdocs/diagnostics/missing-module-on-known-paths.md

@@ -1,5 +1,9 @@
-# Missing Module On Known Path From A Dependency Note (`MissingModuleOnKnownPaths`)
+# Missing module on known path from a dependency (MissingModuleOnKnownPaths)
 
+Notes related to information about a missing module dependency.
+
+
+## Overview
 
 This diagnostic group covers notes related to displaying information about a missing module dependency which the compiler is able to locate as present on a search path found in a loaded Swift binary module, but which is not specified to the current compilation.
 
@@ -15,4 +19,5 @@ The Swift compiler would emit a module-not-found error and a note to inform the
 error: Compilation search paths unable to resolve module dependency: 'Bar' [#MissingModuleOnKnownPaths]
 note: 'Bar' can be found using a search path that was specified when building module 'Foo' ('<Search Path>'). This search path was not specified on the current compilation.
 ```
+
 Some prior versions of the Swift compiler erroneously inherited search paths from loaded binary Swift modules and used them to resolve other, subsequently-encountered module dependencies. All search paths required to resolve direct and transitive module dependencies must be explicitly specified on the compiler invocation which will encounter these dependencies.