py/repl: Refactor autocomplete to reduce nesting.

Originally at adafruit#4548

Signed-off-by: Artyom Skrobov <tyomitch@gmail.com>

py/repl.c

@@ -161,15 +161,22 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
     mp_obj_t obj = MP_OBJ_FROM_PTR(&mp_module___main__);
     mp_obj_t dest[2];
 
+    const char *s_start;
+    size_t s_len;
+
     for (;;) {
         // get next word in string to complete
-        const char *s_start = str;
+        s_start = str;
         while (str < top && *str != '.') {
             ++str;
         }
-        size_t s_len = str - s_start;
+        s_len = str - s_start;
+
+        if (str == top) {
+            // end of string, do completion on this partial name
+            break;
+        }
 
-        if (str < top) {
         // a complete word, lookup in current object
         qstr q = qstr_find_strn(s_start, s_len);
         if (q == MP_QSTRnull) {
@@ -186,9 +193,7 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
 
         // skip '.' to move to next word
         ++str;
-
-        } else {
-            // end of string, do completion on this partial name
+    }
 
     // look for matches
     const char *match_str = NULL;
@@ -284,8 +289,6 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
     mp_print_str(print, "\n");
 
     return (size_t)(-1); // indicate many matches
-        }
-    }
 }
 
 #endif // MICROPY_HELPER_REPL