histograms: add ShareRanking leveldb suffix

I forgot to do this in r891356 when I added the new database client.

Bug: 1201846
Change-Id: I46315e28e53186b528dbed9eaf4d4ba3c55908b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2988287
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#896106}

tools/metrics/histograms/histograms_xml/histogram_suffixes_list.xml

@@ -8679,6 +8679,8 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   <suffix name="SharedDb" label="Shared database"/>
   <suffix name="ShareHistoryDatabase"
       label="Database for third-party share history."/>
+  <suffix name="ShareRankingDatabase"
+      label="Database for third-party share rankings."/>
   <suffix name="SignalDatabase" label="Segmentation platform signal database."/>
   <suffix name="SignalStorageConfigDatabase"
       label="Segmentation platform signal storage config."/>