Fix according to coding convention

- Don't define global variables
- add command prefix to avoid conflicting names

src/_yfm

@@ -35,27 +35,23 @@
 #
 # ------------------------------------------------------------------------------
 
-_commands=(
-  'publish:Publish built documentation in target aws s3 compatible storage'
-  'translate:Translate documentation from source to target language using configured translation provider'
-)
-
-_suggest_dir() {
+_yfm_suggest_dir() {
   _alternative 'directory::_directories' ':current directory:(.)' && return 0
 }
 
-_yfm_commands() {
-  _describe 'commands' _commands
-}
-
 _yfm() {
   local context state state_descr line
   typeset -A opt_args
 
+  local commands=(
+    'publish:Publish built documentation in target aws s3 compatible storage'
+    'translate:Translate documentation from source to target language using configured translation provider'
+  )
+
   _arguments \
     '(- *)'{-h,--help}'[Show help message]' \
-    '(-i --input)'{-i,--input}'[Configure path to yfm input directory]:dir:_suggest_dir' \
-    '(-o --output)'{-o,--output}'[Configure path to yfm output directory]:dir:_suggest_dir' \
+    '(-i --input)'{-i,--input}'[Configure path to yfm input directory]:dir:_yfm_suggest_dir' \
+    '(-o --output)'{-o,--output}'[Configure path to yfm output directory]:dir:_yfm_suggest_dir' \
     '(--varsPreset)'--varsPreset'[Name of the variable preset used]:TEXT' \
     '(--vars -v)'{--vars,-v}'[Values of variables]:TEXT' \
     '(--strict -s)'{--strict,-s}'[Launch in strict mode]' \
@@ -69,7 +65,7 @@ _yfm() {
     '(--lint-disabled)'--lint-disabled'[Should whether to turn off a linter]' \
     '(--build-disabled)'--build-disabled'[Should whether to turn off a build]' \
     '(--add-map-file)'--add-map-file'[hould add all paths of documentation into file.json]' \
-    '1: :_yfm_commands' \
+    '1: :(($commands))' \
     '*:: :->command_args'
 
   case $state in
@@ -92,8 +88,8 @@ _yfm() {
           _arguments \
             '(--source)'--source'[Language code of the original document in ISO 639-1 format]:TEXT' \
             '(--target)'--target'[Language code of the translated document in ISO 639-1 format]:TEXT' \
-            '(--input)'--input'[Source path to the documentation]:dir:_suggest_dir' \
-            '(--target)'--target'[Target path to the translated documentation]:dir:_suggest_dir' \
+            '(--input)'--input'[Source path to the documentation]:dir:_yfm_suggest_dir' \
+            '(--target)'--target'[Target path to the translated documentation]:dir:_yfm_suggest_dir' \
             '(--include)'--include'[A set of rules for filtering sent translation files]:filename:_files' \
             '(--exclude)'--exclude'[A set of rules prohibiting sending files for translation]:filename:_files' \
             '*:: :->command_args'