Document tests a bit more

Author: GuillaumeGomez

src/test/rustdoc/deref-recursive-pathbuf.rs

@@ -1,5 +1,6 @@
 // #26207: Show all methods reachable via Deref impls, recursing through multiple dereferencing
 // levels and across multiple crates.
+// For `Deref` on non-foreign types, look at `deref-recursive.rs`.
 
 // @has 'foo/struct.Foo.html'
 // @has '-' '//*[@id="deref-methods-PathBuf"]' 'Methods from Deref<Target = PathBuf>'

src/test/rustdoc/deref-recursive.rs

@@ -1,5 +1,6 @@
 // #26207: Show all methods reachable via Deref impls, recursing through multiple dereferencing
 // levels if needed.
+// For `Deref` on foreign types, look at `deref-recursive-pathbuf.rs`.
 
 // @has 'foo/struct.Foo.html'
 // @has '-' '//*[@id="deref-methods-Bar"]' 'Methods from Deref<Target = Bar>'

src/test/rustdoc/recursive-deref.rs

@@ -50,6 +50,7 @@ impl G {
 }
 
 // @has recursive_deref/struct.D.html '//h3[@class="code-header in-band"]' 'impl Deref for D'
+// We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]'
 impl Deref for D {
     type Target = E;
@@ -60,6 +61,7 @@ impl Deref for D {
 }
 
 // @has recursive_deref/struct.E.html '//h3[@class="code-header in-band"]' 'impl Deref for E'
+// We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]'
 impl Deref for E {
     type Target = F;
@@ -70,6 +72,7 @@ impl Deref for E {
 }
 
 // @has recursive_deref/struct.F.html '//h3[@class="code-header in-band"]' 'impl Deref for F'
+// We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]'
 impl Deref for F {
     type Target = G;