[COIL] Change chromium code search type links to use main rather than…

… master for sql

    See this doc: go/chromium-coil-change for more info
    BUG=1210385

Change-Id: I5ecb4df810648b9b37c4e2202b58c46c08d1754d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2901729
Auto-Submit: John Palmer <jopalmer@chromium.org>
Reviewed-by: Chris Mumford <cmumford@google.com>
Commit-Queue: John Palmer <jopalmer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#884752}

sql/DIR_METADATA

@@ -1,10 +1,10 @@
 # Metadata information for this directory.
 #
 # For more information on DIR_METADATA files, see:
-#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/README.md
+#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/README.md
 #
 # For the schema of this file, see Metadata message:
-#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/proto/dir_metadata.proto
+#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/proto/dir_metadata.proto
 
 monorail {
   component: "Internals>Storage"