refactor(install): remove trailing slash from BIN_DIR (#3723)

The installation script warns about `BIN_DIR` not being found in `$PATH`
when the users pass a trailing forward slash.

This has been discussed in #1310, #1341, and #3486.

Fixes #3493

install/install.sh

@@ -263,7 +263,7 @@ confirm() {
 }
 
 check_bin_dir() {
-  bin_dir="$1"
+  bin_dir="${1%/}"
 
   if [ ! -d "$BIN_DIR" ]; then
     error "Installation location $BIN_DIR does not appear to be a directory"
@@ -276,7 +276,7 @@ check_bin_dir() {
   good=$(
     IFS=:
     for path in $PATH; do
-      if [ "${path}" = "${bin_dir}" ]; then
+      if [ "${path%/}" = "${bin_dir}" ]; then
         printf 1
         break
       fi