qapi: Fix misspelled section tags in doc comments

Section tags are case sensitive and end with a colon.  Screwing up
either gets them interpreted as ordinary paragraph.  Fix a few.

Fixes: 4e88e7e340 (qapi/qom: Define cache enumeration and properties for machine, 2024-11-01)
Fixes: 8eb6d39e22 (qom: qom-list-get, 2025-07-11)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20260701061136.798815-1-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>

qapi/machine-common.json

@@ -108,7 +108,7 @@
 #
 # @caches: the list of `SmpCacheProperties`.
 #
-# Since 9.2
+# Since: 9.2
 ##
 { 'struct': 'SmpCachePropertiesWrapper',
   'data': { 'caches': ['SmpCacheProperties'] } }

qapi/qom.json

@@ -58,7 +58,7 @@
 # @value: the value of the property.  Absent when the property cannot
 #     be read.
 #
-# Since 10.1
+# Since: 10.1
 ##
 { 'struct': 'ObjectPropertyValue',
   'data': { 'name': 'str',
@@ -70,7 +70,7 @@
 #
 # @properties: a list of properties.
 #
-# Since 10.1
+# Since: 10.1
 ##
 { 'struct': 'ObjectPropertiesValues',
   'data': { 'properties': [ 'ObjectPropertyValue' ] }}
@@ -167,7 +167,7 @@
 # Returns: A list where each element is the result for the
 #     corresponding element of @paths.
 #
-# Since 10.1
+# Since: 10.1
 ##
 { 'command': 'qom-list-get',
   'data': { 'paths': [ 'str' ] },