Fix #42. Clarify escaping when EL is integrated with other technologies

Signed-off-by: Mark Thomas <markt@apache.org>

spec/src/main/asciidoc/ELSpec.adoc

diff --git a/spec/src/main/asciidoc/ELSpec.adoc b/spec/src/main/asciidoc/ELSpec.adoc
index 75bd7a5..80c1fd2 100644
--- a/spec/src/main/asciidoc/ELSpec.adoc
+++ b/spec/src/main/asciidoc/ELSpec.adoc
@@ -384,6 +384,12 @@
 then apply if the return type of the method expression is not
 `java.lang.String`.
 
+Note that when EL is integrated into other technologies, such as JSP,
+that integration may not include Literal Expressions. Where integrations
+do not include Literal Expressions, those integrating technologies will
+define their own specification, including escaping rules, for handling
+text outside of EL and the escaping rules described above will not apply.
+
 ==== Composite expressions
 
 The EL also supports _composite expressions_