patch 8.1.0351: 'incsearch' for :/foo/s//<Esc> changes last search pattern

Problem:    'incsearch' for :/foo/s//<Esc> changes last search pattern.
Solution:   Save the last search pattern earlier.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 5b53785..7677917 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -2911,6 +2911,7 @@
 
 /*
  * Parse the address range, if any, in "eap".
+ * May set the last search pattern.
  * Return FAIL and set "errormsg" or return OK.
  */
     int
@@ -4436,10 +4437,11 @@
 }
 
 /*
- * get a single EX address
+ * Get a single EX address.
  *
  * Set ptr to the next character after the part that was interpreted.
  * Set ptr to NULL when an error is encountered.
+ * This may set the last used search pattern.
  *
  * Return MAXLNUM when no Ex address was found.
  */