shell-integration: remove redundant comments

I think the conditions are sufficiently self-descriptive.

src/shell-integration/bash/ghostty.bash

@@ -75,7 +75,6 @@ fi
 
 # Add Ghostty binary to PATH if the path feature is enabled
 if [[ "$GHOSTTY_SHELL_FEATURES" == *"path"* && -n "$GHOSTTY_BIN_DIR" ]]; then
-  # Check if the directory is already in PATH
   if [[ ":$PATH:" != *":$GHOSTTY_BIN_DIR:"* ]]; then
     export PATH="$PATH:$GHOSTTY_BIN_DIR"
   fi

src/shell-integration/elvish/lib/ghostty-integration.elv

@@ -197,7 +197,6 @@
     set edit:after-readline  = (conj $edit:after-readline {|_| block })
   }
   if (and (has-value $features path) (has-env GHOSTTY_BIN_DIR)) {
-    # Check if the directory is already in PATH
     if (not (has-value $paths $E:GHOSTTY_BIN_DIR)) {
         set paths = [$E:GHOSTTY_BIN_DIR $@paths]
     }

src/shell-integration/zsh/ghostty-integration

@@ -222,7 +222,6 @@ _ghostty_deferred_init() {
 
     # Add Ghostty binary to PATH if the path feature is enabled
     if [[ "$GHOSTTY_SHELL_FEATURES" == *"path"* ]] && [[ -n "$GHOSTTY_BIN_DIR" ]]; then
-      # Check if the directory is already in PATH
       if [[ ":$PATH:" != *":$GHOSTTY_BIN_DIR:"* ]]; then
         builtin export PATH="$PATH:$GHOSTTY_BIN_DIR"
       fi