InputContainer: Fall cleanup ;).

Get rid of the doc & seqtext fields, as they are not actually used (nor
are they particularly useful, the event handler's name should be pretty
self-explanatory).

Also, tweak the key_events documentation to highlight the quirks of the
API, especially as far as array nesting is involved...

Random drive-by cleanup of the declarations of key_events & ges_events
to re-use the existing instance object (now that we know they're sane
;p) for tables with a single member (less GC pressure).

frontend/apps/reader/modules/readerrotation.lua

@@ -12,13 +12,15 @@ function ReaderRotation:init()
         self.key_events = {
             -- these will all generate the same event, just with different arguments
             RotateLeft = {
-                {"J"},
-                doc = "rotate left by 90 degrees",
-                event = "Rotate", args = -90 },
+                { "J" },
+                event = "Rotate",
+                args = -90
+            },
             RotateRight = {
-                {"K"},
-                doc = "rotate right by 90 degrees",
-                event = "Rotate", args = 90 },
+                { "K" },
+                event = "Rotate",
+                args = 90
+            },
         }
     end
 end