[completion] Add support for HostName lines in ~/.ssh/config (#1785)

Close #1783

shell/completion.bash

@@ -244,7 +244,7 @@ _fzf_complete_telnet() {
 
 _fzf_complete_ssh() {
   _fzf_complete '+m' "$@" < <(
-    cat <(cat ~/.ssh/config ~/.ssh/config.d/* /etc/ssh/ssh_config 2> /dev/null | command grep -i '^host ' | command grep -v '[*?]' | awk '{for (i = 2; i <= NF; i++) print $1 " " $i}') \
+    cat <(cat ~/.ssh/config ~/.ssh/config.d/* /etc/ssh/ssh_config 2> /dev/null | command grep -i '^\s*host\(name\)\? ' | command grep -v '[*?]' | awk '{for (i = 2; i <= NF; i++) print $1 " " $i}') \
         <(command grep -oE '^[[a-z0-9.,:-]+' ~/.ssh/known_hosts | tr ',' '\n' | tr -d '[' | awk '{ print $1 " " $1 }') \
         <(command grep -v '^\s*\(#\|$\)' /etc/hosts | command grep -Fv '0.0.0.0') |
         awk '{if (length($2) > 0) {print $2}}' | sort -u

shell/completion.zsh

@@ -115,7 +115,7 @@ _fzf_complete_telnet() {
 _fzf_complete_ssh() {
   _fzf_complete '+m' "$@" < <(
     setopt localoptions nonomatch
-    command cat <(cat ~/.ssh/config ~/.ssh/config.d/* /etc/ssh/ssh_config 2> /dev/null | command grep -i '^host ' | command grep -v '[*?]' | awk '{for (i = 2; i <= NF; i++) print $1 " " $i}') \
+    command cat <(cat ~/.ssh/config ~/.ssh/config.d/* /etc/ssh/ssh_config 2> /dev/null | command grep -i '^\s*host\(name\)\? ' | command grep -v '[*?]' | awk '{for (i = 2; i <= NF; i++) print $1 " " $i}') \
         <(command grep -oE '^[[a-z0-9.,:-]+' ~/.ssh/known_hosts | tr ',' '\n' | tr -d '[' | awk '{ print $1 " " $1 }') \
         <(command grep -v '^\s*\(#\|$\)' /etc/hosts | command grep -Fv '0.0.0.0') |
         awk '{if (length($2) > 0) {print $2}}' | sort -u