qapi/block.json: Add newline after "Example:" for block-latency-histogram-set

The block-latency-histogram-set command is the only one which uses
the Example/Examples section with the first line of the documentation
immediately following the ':'. Bring it into line with the rest.

This will allow us to avoid special-casing the indentation handling
for "Examples" sections; instead for Examples as for any other section
header these two indentations will be equivalent:

Examples:
Line one
Line two

Examples: Line one
          Line two

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-3-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

qapi/block.json

@@ -528,7 +528,8 @@
 #
 # Since: 4.0
 #
-# Example: set new histograms for all io types with intervals
+# Example:
+# set new histograms for all io types with intervals
 # [0, 10), [10, 50), [50, 100), [100, +inf):
 #
 # -> { "execute": "block-latency-histogram-set",
@@ -536,7 +537,8 @@
 #                     "boundaries": [10, 50, 100] } }
 # <- { "return": {} }
 #
-# Example: set new histogram only for write, other histograms will remain
+# Example:
+# set new histogram only for write, other histograms will remain
 # not changed (or not created):
 #
 # -> { "execute": "block-latency-histogram-set",
@@ -544,7 +546,8 @@
 #                     "boundaries-write": [10, 50, 100] } }
 # <- { "return": {} }
 #
-# Example: set new histograms with the following intervals:
+# Example:
+# set new histograms with the following intervals:
 #   read, flush: [0, 10), [10, 50), [50, 100), [100, +inf)
 #   write: [0, 1000), [1000, 5000), [5000, +inf)
 #
@@ -554,7 +557,8 @@
 #                     "boundaries-write": [1000, 5000] } }
 # <- { "return": {} }
 #
-# Example: remove all latency histograms:
+# Example:
+# remove all latency histograms:
 #
 # -> { "execute": "block-latency-histogram-set",
 #      "arguments": { "id": "drive0" } }