Escape '{reference}' elements in asciidoc files

Escape lines that look like variable references but should actually be
included verbatim.

Closes gh-17386

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/asciidoc/endpoints/caches.adoc

@@ -30,7 +30,7 @@ include::{snippets}caches/all/response-fields.adoc[]
 
 [[caches-named]]
 == Retrieving Caches by Name
-To retrieve a cache by name, make a `GET` request to `/actuator/caches/{name}`,
+To retrieve a cache by name, make a `GET` request to `/actuator/caches/\{name}`,
 as shown in the following curl-based example:
 
 include::{snippets}caches/named/curl-request.adoc[]
@@ -74,7 +74,7 @@ include::{snippets}caches/evict-all/curl-request.adoc[]
 
 [[caches-evict-named]]
 == Evict a Cache by Name
-To evict a particular cache, make a `DELETE` request to `/actuator/caches/{name}` as shown
+To evict a particular cache, make a `DELETE` request to `/actuator/caches/\{name}` as shown
 in the following curl-based example:
 
 include::{snippets}caches/evict-named/curl-request.adoc[]

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/asciidoc/endpoints/health.adoc

@@ -30,7 +30,7 @@ include::{snippets}health/response-fields.adoc[]
 [[health-retrieving-component]]
 == Retrieving the Health of a component
 To retrieve the health of a particular component of the application, make a `GET` request
-to `/actuator/health/{component}`, as shown in the following curl-based example:
+to `/actuator/health/\{component}`, as shown in the following curl-based example:
 
 include::{snippets}health/component/curl-request.adoc[]
 
@@ -54,7 +54,7 @@ include::{snippets}health/component/response-fields.adoc[]
 == Retrieving the Health of a component instance
 If a particular component consists of multiple instances (as the `broker` indicator in
 the example above), the health of a particular instance of that component can be retrieved
-by issuing a `GET` request to `/actuator/health/{component}/{instance}`, as shown in the
+by issuing a `GET` request to `/actuator/health/\{component}/\{instance}`, as shown in the
 following curl-based example:
 
 include::{snippets}health/instance/curl-request.adoc[]

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/asciidoc/endpoints/sessions.adoc

@@ -48,7 +48,7 @@ include::{snippets}sessions/username/response-fields.adoc[]
 [[sessions-retrieving-id]]
 == Retrieving a Single Session
 
-To retrieve a single session, make a `GET` request to `/actuator/sessions/{id}`, as
+To retrieve a single session, make a `GET` request to `/actuator/sessions/\{id}`, as
 shown in the following curl-based example:
 
 include::{snippets}sessions/id/curl-request.adoc[]
@@ -75,7 +75,7 @@ include::{snippets}sessions/id/response-fields.adoc[]
 [[sessions-deleting]]
 == Deleting a Session
 
-To delete a session, make a `DELETE` request to `/actuator/sessions/{id}`, as shown in
+To delete a session, make a `DELETE` request to `/actuator/sessions/\{id}`, as shown in
 the following curl-based example:
 
 include::{snippets}sessions/delete/curl-request.adoc[]

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/asciidoc/index.adoc

@@ -26,7 +26,7 @@ Before you proceed, you should read the following topics:
 === URLs
 
 By default, all web endpoints are available beneath the path `/actuator` with URLs of
-the form `/actuator/{id}`. The `/actuator` base path can be configured by using the
+the form `/actuator/\{id}`. The `/actuator` base path can be configured by using the
 `management.endpoints.web.base-path` property, as shown in the following example:
 
 [source,properties,indent=0]
@@ -35,7 +35,7 @@ the form `/actuator/{id}`. The `/actuator` base path can be configured by using
 ----
 
 The preceding `application.properties` example changes the form of the endpoint URLs from
-`/actuator/{id}` to `/manage/{id}`. For example, the URL `info` endpoint would become
+`/actuator/\{id}` to `/manage/\{id}`. For example, the URL `info` endpoint would become
 `/manage/info`.