general: Miscellaneous documentation updates

- Add missing documentation for options and environment variables
- Rearrange definition and documentation of 'Options', 'Variables'
  and 'Aliases' in a consistent order

modules/completion/README.md

@@ -6,6 +6,19 @@ the [zsh-completions][1] project.
 
 This module must be loaded **after** the *utility* module.
 
+Options
+-------
+
+  - `COMPLETE_IN_WORD` complete from both ends of a word.
+  - `ALWAYS_TO_END` move cursor to the end of a completed word.
+  - `PATH_DIRS` perform path search even on command names with slashes.
+  - `AUTO_MENU` show completion menu on a successive tab press.
+  - `AUTO_LIST` automatically list choices on ambiguous completion.
+  - `AUTO_PARAM_SLASH` if completed parameter is a directory, add a trailing slash.
+  - `EXTENDED_GLOB` needed for file modification glob modifiers with compinit.
+  - `MENU_COMPLETE` do not autoselect the first completion entry.
+  - `FLOW_CONTROL` disable start/stop characters in shell editor.
+
 Settings
 --------
 

modules/completion/init.zsh

@@ -99,7 +99,7 @@ zstyle ':completion:*:history-words' remove-all-dups yes
 zstyle ':completion:*:history-words' list false
 zstyle ':completion:*:history-words' menu yes
 
-# Environmental Variables
+# Environment Variables
 zstyle ':completion::*:(-command-|export):*' fake-parameters ${${${_comps[(I)-value-*]#*,}%%,*}:#-*-}
 
 # Populate hostname completion. But allow ignoring custom entries from static