perf: remove unnecessary subshells in command -v checks

Replace 'if (command -v x &>/dev/null); then' with
'if command -v x &>/dev/null; then' across completion.d, rc.d and
profile.d. Parentheses forced a subshell fork for every 'if' check,
which is unnecessary overhead since command -v runs fine in the
current shell.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rc.d/direnv

@@ -1,4 +1,4 @@
-if (asdf which direnv &>/dev/null); then
+if asdf which direnv &>/dev/null; then
 	# Hook direnv into your shell.
 	eval "$(asdf exec direnv hook bash)"
 
@@ -7,7 +7,7 @@ if (asdf which direnv &>/dev/null); then
 
 	return
 
-elif (command -v direnv &>/dev/null); then
+elif command -v direnv &>/dev/null; then
 	# Hook direnv into your shell.
 	eval "$(direnv hook bash)"