DOC: config: add missing context hint for new server and proxy keywords

To stay consistent with the work started in 54627f9 ("DOC: config: add
context hint for proxy keywords") and 3d4e1e6 ("DOC: config: add context
hint for server keywords"), we add missing context hint for "guid" (both
proxy and server) keyword and "hash-key" server keyword that were added
during 3.0 development.

This may be backported in 3.0.

(cherry picked from commit c157894)
Signed-off-by: Christopher Faulet <[email protected]>

Author: Darlelet

doc/configuration.txt

@@ -6955,6 +6955,8 @@ fullconn <conns>
 guid <string>
   Specify a case-sensitive global unique ID for this proxy.
 
+  May be used in the following contexts: tcp, http, log
+
   May be used in sections :   defaults | frontend | listen | backend
                                  no    |    yes   |   yes  |   yes
 
@@ -17155,11 +17157,15 @@ force-tlsv13
   "ssl-default-server-options". See also "ssl-min-ver" and ssl-max-ver".
 
 guid <string>
+  May be used in the following contexts: tcp, http, log
+
   Specify a case-sensitive global unique ID for this server. This must be
   unique across all haproxy configuration on every object types. See "guid"
   proxy keyword description for more information on its format.
 
 hash-key <key>
+  May be used in the following contexts: tcp, http, log
+
   Specify how "hash-type consistent" node keys are computed
 
   Arguments :