doc: fix webcrypto.md AES-GCM backticks

PR-URL: nodejs#54621
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/webcrypto.md

@@ -567,7 +567,7 @@ The algorithms currently supported include:
 * `'RSA-OAEP'`
 * `'AES-CTR'`
 * `'AES-CBC'`
-* `'AES-GCM`'
+* `'AES-GCM'`
 
 ### `subtle.deriveBits(algorithm, baseKey[, length])`
 
@@ -703,7 +703,7 @@ The algorithms currently supported include:
 * `'RSA-OAEP'`
 * `'AES-CTR'`
 * `'AES-CBC'`
-* `'AES-GCM`'
+* `'AES-GCM'`
 
 ### `subtle.exportKey(format, key)`