refactor(__load_completion): handle backslash always at start of command

Previously, we handled it at the start of the command's _basename_. Even
though the backslash doesn't make a practical difference with regards to
aliases with paths, it seems more logical and clearer to handle it this
way.

When invoked as just the basename, this does not change anything.

Author: scop

bash_completion

@@ -2500,6 +2500,14 @@ __load_completion()
     local -a paths
     [[ $cmdname ]] || return 1
 
+    local backslash=
+    if [[ $cmd == \\* ]]; then
+        cmd=${cmd:1}
+        # If we already have a completion for the "real" command, use it
+        $(complete -p "$cmd" 2>/dev/null || echo false) "\\$cmd" && return 0
+        backslash=\\
+    fi
+
     local -a dirs=()
 
     # Lookup order:
@@ -2538,14 +2546,6 @@ __load_completion()
     _comp_split -F : paths "${XDG_DATA_DIRS:-/usr/local/share:/usr/share}"
     dirs+=("${paths[@]/%//bash-completion/completions}")
 
-    local backslash=
-    if [[ $cmdname == \\* ]]; then
-        cmdname=${cmdname:1}
-        # If we already have a completion for the "real" command, use it
-        $(complete -p "$cmdname" 2>/dev/null || echo false) "\\$cmdname" && return 0
-        backslash=\\
-    fi
-
     # For loading 3rd party completions wrapped in shopt reset
     local IFS=$' \t\n'