patch 8.1.1909: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make a few more functions usable as a method.
diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 84aeb57..f2f72bd 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -238,6 +238,10 @@
 		mention that.
 		Mainly useful with |terminal-diff|.
 
+		Can also be used as a |method|: >
+			GetLog()->assert_equalfile('expected.log')
+
+
 assert_exception({error} [, {msg}])			*assert_exception()*
 		When v:exception does not contain the string {error} an error
 		message is added to |v:errors|.  Also see |assert-return|.
@@ -322,10 +326,15 @@
 		Can also be used as a |method|: >
 			getFile()->assert_notmatch('bar.*')
 
+
 assert_report({msg})					*assert_report()*
 		Report a test failure directly, using {msg}.
 		Always returns one.
 
+		Can also be used as a |method|: >
+			GetMessage()->assert_report()
+
+
 assert_true({actual} [, {msg}])				*assert_true()*
 		When {actual} is not true an error message is added to
 		|v:errors|, like with |assert_equal()|.