Fix typos (mighty-gerbils#1034)

src/std/make.ss

@@ -925,4 +925,4 @@ TODO:
 ;; appends flags together; useful for -cc-options and -ld-options
 (def (append-options . opts)
   (let (opts (filter (? (not string-empty?)) opts))
-    (string-join opts " ")))
+    (string-join opts " ")))

src/std/misc/alist.ss

@@ -52,7 +52,7 @@
 
 ;; Note how the current implementation ensures that the cons cell whose car
 ;; holds the value for a given key will never change, though there is
-;; currently no agetq-cell function to get to it.
+;; currently no assgetq-cell function to get to it.
 ;; Also, we privilege recently added keys by pushing them to the front of the
 ;; alist rather than to its end.
 (defrule (define-aset! aset! cmp)