CLEANUP: assorted typo fixes in the code and comments

This is 30th iteration of typo fixes
diff --git a/reg-tests/ssl/dynamic_server_ssl.vtc b/reg-tests/ssl/dynamic_server_ssl.vtc
index 84854a3..0e6ecb5 100644
--- a/reg-tests/ssl/dynamic_server_ssl.vtc
+++ b/reg-tests/ssl/dynamic_server_ssl.vtc
@@ -1,5 +1,5 @@
 #REGTEST_TYPE=bug
-# Test if a certicate can be dynamically updated once a server which used it
+# Test if a certificate can be dynamically updated once a server which used it
 # was removed.
 #
 varnishtest "Delete server via cli and update certificates"
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 93a24f0..4a0085f 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -3276,7 +3276,7 @@
 }
 
 /* Decrement the <qc> refcount. If the refcount is zero *BEFORE* the
- * substraction, the quic_conn is freed.
+ * subtraction, the quic_conn is freed.
  */
 static void quic_conn_drop(struct quic_conn *qc)
 {