Fix usages of global variables

- Lint references to unknown fields of modules, excluding the keys and
   colours modules. This caught several silly errors in our stub files,
   but nothing else.
 - Lint on using unknown globals. This highlighted a couple of really
   silly mistakes. Fixes #427.
 - Add documentation for fs.attributes, fs.getCapacity and pocket, as
   they were not defined before.

Co-authored-by: JackMacWindows <jackmacwindowslinux@gmail.com>

doc/stub/fs.lua

@@ -19,6 +19,36 @@ function getFreeSpace(path) end
 function find(pattern) end
 function getDir(path) end
 
+--- Get the capacity of the drive at the given path.
+--
+-- This may be used in conjunction with @{getFreeSpace} to determine what
+-- percentage of this drive has been used.
+--
+-- @tparam string path The path of the drive to get.
+-- @treturn number This drive's capacity. This will be 0 for "read-only" drives,
+-- such as the ROM or treasure disks.
+function getCapacity(path) end
+
+--- Get attributes about a specific file or folder.
+--
+-- The returned attributes table contains information about the size of the
+-- file, whether it is a directory, and when it was created and last modified.
+--
+-- The creation and modification times are given as the number of milliseconds
+-- since the UNIX epoch. This may be given to @{os.date} in order to convert it
+-- to more usable form.
+--
+-- @tparam string path The path to get attributes for.
+-- @treturn { size = number, isDir = boolean, created = number, modified = number }
+-- The resulting attributes.
+-- @throws If the path does not exist.
+-- @see getSize If you only care about the file's size.
+-- @see isDir If you only care whether a path is a directory or not.
+function attributes(path) end
+
+-- Defined in bios.lua
+function complete(sPath, sLocation, bIncludeFiles, bIncludeDirs) end
+
 --- A file handle which can be read from.
 --
 -- @type ReadHandle

doc/stub/os.lua

@@ -15,3 +15,10 @@ function cancelTimer(id) end
 function cancelAlarm(id) end
 function epoch(timezone) end
 function date(format, time) end
+
+-- Defined in bios.lua
+function loadAPI(path) end
+function pullEvent(filter) end
+function pullEventRaw(filter) end
+function version() end
+function run(env, path, ...) end

doc/stub/pocket.lua

@@ -0,0 +1,28 @@
+--[[-
+Control the current pocket computer, adding or removing upgrades.
+
+This API is only available on pocket computers. As such, you may use its
+presence to determine what kind of computer you are using:
+
+```lua
+if pocket then
+  print("On a pocket computer")
+else
+  print("On something else")
+end
+```
+]]
+
+--- Search the player's inventory for another upgrade, replacing the existing
+-- one with that item if found.
+--
+-- This inventory search starts from the player's currently selected slot,
+-- allowing you to prioritise upgrades.
+--
+-- @throws If an upgrade cannot be found.
+function equipBack() end
+
+--- Remove the pocket computer's current upgrade.
+--
+-- @throws If this pocket computer does not currently have an upgrade.
+function unequipBack() end

doc/stub/redstone.lua

@@ -11,4 +11,4 @@ setAnalogueOutput = setAnalogOutput
 function getAnalogOutput(sid) end
 getAnalogueOutput = getAnalogOutput
 function getAnalogInput(side) end
-getAnalogueInput = getAnaloguInput
+getAnalogueInput = getAnalogInput

doc/stub/term.lua

@@ -15,14 +15,14 @@ isColor = isColour
 function getTextColour() end
 getTextColor = getTextColor
 function getBackgroundColour() end
-getBackgroundColour = getBackgroundColour
+getBackgroundColor = getBackgroundColour
 function blit(text, text_colours, background_colours) end
 function setPaletteColour(colour, ...) end
-setPaletteColour = setPaletteColour
+setPaletteColor = setPaletteColour
 function getPaletteColour(colour, ...) end
-getPaletteColour = getPaletteColour
+getPaletteColor = getPaletteColour
 function nativePaletteColour(colour) end
-nativePaletteColour = nativePaletteColour
+nativePaletteColor = nativePaletteColour
 
 --- @type Redirect
 local Redirect = {}