feat(history-substring-search): add `prefixed` setting

support zsh-history-substring-search `HISTORY_SUBSTRING_SEARCH_PREFIXED` env

Signed-off-by: mritd <mritd@linux.com>

modules/history-substring-search/README.md

@@ -63,6 +63,12 @@ _`${ZDOTDIR:-$HOME}/.zpreztorc`_:
 
 ```sh
 zstyle ':prezto:module:history-substring-search' globbing-flags ''
+
+To set the search matched against the start of each history entry, add the following line to
+_`${ZDOTDIR:-$HOME}/.zpreztorc`_:
+
+```sh
+zstyle ':prezto:module:history-substring-search' prefixed 'yes'
 ```
 
 ### Fuzzy search

modules/history-substring-search/init.zsh

@@ -34,6 +34,10 @@ if zstyle -t ':prezto:module:history-substring-search' case-sensitive; then
   HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS="${HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS//i}"
 fi
 
+if zstyle -t ':prezto:module:history-substring-search' prefixed; then
+  HISTORY_SUBSTRING_SEARCH_PREFIXED='true'
+fi
+
 if ! zstyle -t ':prezto:module:history-substring-search' color; then
   unset HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_{FOUND,NOT_FOUND}
 fi