Fix kEnableSignedExchangeSubresourcePrefetchDescription

I submitted crrev.com/c/1619582 before fixing misspelling.

TBR=ksakamoto@chromium.org

Bug: 935267
Change-Id: I7611ccabbf05bbc6d7139efde3a1275537abf16c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619592Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661326}

chrome/browser/flag_descriptions.cc

@@ -44,7 +44,7 @@ const char kEnableSignedExchangeSubresourcePrefetchDescription[] =
     "alternative signed exchange subresources by setting \"alternate\" link "
     "header. Chrome will prefetch the alternate signed exchange subresources "
     "and will load them if the publisher of the main signed exchange has set "
-    "\"allowed-alt-sxg\" link header in the signed innere response of the "
+    "\"allowed-alt-sxg\" link header in the signed inner response of the "
     "main signed exchange.";
 
 const char kAllowStartingServiceManagerOnlyName[] =