fix nits in aml manual page

Reference: /n/atom/patch/applied2013/amlmanupd
Date: Wed Oct  9 01:22:16 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/man/2/aml	Wed Oct  9 01:22:07 2013
+++ /sys/man/2/aml	Wed Oct  9 01:22:08 2013
@@ -153,10 +153,10 @@
 and
 .IR type .
 .TP
-.IR amltake( p )
+.BI amltake( p )
 Exclude object from garbage collection.
 .TP
-.IR amldrop ( p )
+.BI amldrop ( p )
 Include previously excluded object in garbage collection.
 .TP
 .BI amlwalk( dot ,\  name )
@@ -177,7 +177,7 @@
 for each matching object under
 .IR dot .
 .TP
-.BI amldelay( microsec )
+.BI amlmicrodelay( µs )
 Delay for the given number of microseconds.
 .TP
 .BI amlmapio( io )