[Fix] prevent sed errors when pattern contains #

When `.nvmrc` or alias files contained comments (lines with `#`),
the `#` character could end up in the search pattern passed to sed,
causing "unterminated regular expression" errors because `#` is
used as the sed address delimiter.

This commit fixes the issue in two places:
1. `nvm_alias`: Strip comments from alias file contents before
   returning them, and trim trailing whitespace
2. `nvm_ls`: Escape `#` characters in SEARCH_PATTERN so they're
   treated as literal characters in the sed address

Fixes #3761

nvm.sh

@@ -1294,7 +1294,7 @@ nvm_alias() {
     return 2
   fi
 
-  command awk 'NF' "${NVM_ALIAS_PATH}"
+  command sed 's/#.*//; s/[[:space:]]*$//' "${NVM_ALIAS_PATH}" | command awk 'NF'
 }
 
 nvm_ls_current() {
@@ -1529,7 +1529,7 @@ nvm_ls() {
       PATTERN='v'
       SEARCH_PATTERN='.*'
     else
-      SEARCH_PATTERN="$(nvm_echo "${PATTERN}" | command sed 's#\.#\\\.#g;')"
+      SEARCH_PATTERN="$(nvm_echo "${PATTERN}" | command sed 's#\.#\\\.#g; s|#|\\#|g')"
     fi
     if [ -n "${NVM_DIRS_TO_SEARCH1}${NVM_DIRS_TO_SEARCH2}${NVM_DIRS_TO_SEARCH3}" ]; then
       VERSIONS="$(command find "${NVM_DIRS_TO_SEARCH1}"/* "${NVM_DIRS_TO_SEARCH2}"/* "${NVM_DIRS_TO_SEARCH3}"/* -name . -o -type d -prune -o -path "${PATTERN}*" \