refactor(fzf): adopt code style and simplify function naming (#10514)

plugins/fzf/fzf.plugin.zsh

-function setup_using_base_dir() {
+function fzf_setup_using_base_dir() {
   local fzf_base fzf_shell fzfdirs dir
 
   test -d "${FZF_BASE}" && fzf_base="${FZF_BASE}"
@@ -58,7 +58,7 @@ function setup_using_base_dir() {
 }
 
 
-function setup_using_debian_package() {
+function fzf_setup_using_debian() {
   if (( ! $+commands[dpkg] )) || ! dpkg -s fzf &>/dev/null; then
     # Either not a debian based distro, or no fzf installed
     return 1
@@ -96,7 +96,7 @@ function setup_using_debian_package() {
   return 0
 }
 
-function setup_using_opensuse_package() {
+function fzf_setup_using_opensuse() {
   # OpenSUSE installs fzf in /usr/bin/fzf
   # If the command is not found, the package isn't installed
   (( $+commands[fzf] )) || return 1
@@ -125,7 +125,7 @@ function setup_using_opensuse_package() {
   return 0
 }
 
-function setup_using_openbsd_package() {
+function fzf_setup_using_openbsd() {
   # openBSD installs fzf in /usr/local/bin/fzf
   if [[ "$OSTYPE" != openbsd* ]] || (( ! $+commands[fzf] )); then
     return 1
@@ -149,21 +149,21 @@ function setup_using_openbsd_package() {
   return 0
 }
 
-function indicate_error() {
-    cat >&2 <<EOF
+# Indicate to user that fzf installation not found if nothing worked
+function fzf_setup_error() {
+  cat >&2 <<'EOF'
 [oh-my-zsh] fzf plugin: Cannot find fzf installation directory.
-Please add \`export FZF_BASE=/path/to/fzf/install/dir\` to your .zshrc
+Please add `export FZF_BASE=/path/to/fzf/install/dir` to your .zshrc
 EOF
 }
 
-# Indicate to user that fzf installation not found if nothing worked
-setup_using_openbsd_package \
-    || setup_using_debian_package \
-    || setup_using_opensuse_package \
-    || setup_using_base_dir \
-    || indicate_error
+fzf_setup_using_openbsd \
+  || fzf_setup_using_debian \
+  || fzf_setup_using_opensuse \
+  || fzf_setup_using_base_dir \
+  || fzf_setup_error
 
-unset -f setup_using_opensuse_package setup_using_debian_package setup_using_base_dir indicate_error
+unset -f -m 'fzf_setup_*'
 
 if [[ -z "$FZF_DEFAULT_COMMAND" ]]; then
   if (( $+commands[rg] )); then