Fix comments.

.env

@@ -1,14 +1,14 @@
-# Default: mnemonic of "testwallets" (friends: Alice, Bob, Carol etc.):
+# Default (placeholder): mnemonic of "testwallets" (friends: Alice, Bob, Carol etc.):
 # https://github.com/multiversx/mx-sdk-testwallets/blob/main/users/mnemonic.txt.
 # This works fine for localnet.
 # For the Github workflows, a repository secret is being used.
 export USERS_MNEMONIC="moral volcano peasant pass circle pen over picture flat shop clap goat never lyrics gather prepare woman film husband gravity behind test tiger improve"
 
-# Default: Alice's secret key:
+# Default (placeholder): Alice's secret key:
 # https://github.com/multiversx/mx-sdk-testwallets/blob/main/users/alice.pem.
 # This works fine for localnet.
 # For the Github workflows, a repository secret is being used.
 export SPONSOR_SECRET_KEY=413f42575f7f26fad3317a778771212fdb80245850981e48b58a4f25e344e8f9
 
-# # For the Github workflows, a repository secret is being used.
+# For the Github workflows, a repository secret is being used.
 export MAINNET_PROXY_URL=""