fix aafigure diagram

docs/makefile

@@ -114,7 +114,7 @@ ifneq ($(STAGE),)
 endif
 
 %.png:%.diagram
-	aafigure -o $@ $?
+	aafigure --scale 0.6 -o $@ $?
 ifneq ($(STAGE),)
 	cp $@ $(WEB_PATH)/$@
 endif

docs/write_disk_buffers.diagram

@@ -1,15 +1,15 @@
 
-                   decrypt in place                move buffer ref.
-+----------------+ (no copy)        +------------+ (no copy)         +------------+
-| receive buffer +--=-------------->| plain text +--=--------------->| disk cache |
-+----------------+                  | buffer     |                   +------+-----+
-        ^                           +------------+                          |
-        | read() on socket                                 write() to file  | 
-        | (copy)                                           (copy)           | 
+                     "decrypt in place"              "move buffer ref."
++------------------+ "(no copy)"    +--------------+ "(no copy)"     +--------------+
+| "receive buffer" +--=------------>| "plain text" +--=------------->| "disk cache" |
++------------------+                | "buffer"     |                 +------+-------+
+        ^                           +--------------+                        |
+        | "read() on socket"                              "write() to file" |
+        | "(copy)"                                        "(copy)"          |
 ---=----|---------------------------------=---------------------------------|--=----
-        |                        kernel space                               |
+        |                       "kernel space"                              |
         |                                                                   v
-+-------+--------+                                               +-------------------+
-| socket kernel  |                                               | kernel page cache |
-| buffer         |                                               |                   |
-+----------------+                                               +-------------------+
++-------+---------+                                           +---------------------+
+| "socket kernel" |                                           | "kernel page cache" |
+| "buffer"        |                                           |                     |
++-----------------+                                           +---------------------+