fix: ensure consistent unescaping and space handling

Unescape any character following a backslash. This fixes autocompletion
for names with escaped spaces.
For example: `/msg Thor\ Odinson hello`

Signed-off-by: Michael Vetter <jubalh@iodoru.org>

src/tools/autocomplete.c

@@ -237,7 +237,7 @@ autocomplete_complete(Autocomplete ac, const gchar* search_str, gboolean quote,
         // unescape search string
         GString* unescaped = g_string_new("");
         for (const char* p = search_str; *p; p++) {
-            if (*p == '\\' && (*(p + 1) == '"' || *(p + 1) == '\\')) {
+            if (*p == '\\' && (*(p + 1) != '\0')) {
                 p++;
             }
             g_string_append_c(unescaped, *p);