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

This CL finishes the changes for all files not in third_party.
Top level files were missed by the script, docs changes due to multiple entries on the same line which were not caught by script, but manually fixed up.
    See this doc: go/chromium-coil-change for more info
    BUG=1210385

Change-Id: I6d92e2e6fd244174cc370662399fa713a7b8abf5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2927090
Auto-Submit: John Palmer <[email protected]>
Commit-Queue: Jochen Eisinger <[email protected]>
Reviewed-by: Jochen Eisinger <[email protected]>
Cr-Commit-Position: refs/heads/master@{#889685}
diff --git a/WATCHLISTS b/WATCHLISTS
index 0b42058..942ef27 100644
--- a/WATCHLISTS
+++ b/WATCHLISTS
@@ -3,7 +3,7 @@
 # found in the LICENSE file.
 
 # Watchlist Rules
-# Refer: https://chromium.googlesource.com/chromium/src/+/master/docs/infra/watchlists.md
+# Refer: https://chromium.googlesource.com/chromium/src/+/main/docs/infra/watchlists.md
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.