[lint] remove unnecessary boolean not

pre-commit

@@ -1,3 +1,4 @@
 #!/bin/bash -xe
 test "$(grep --max-count 1 version Cargo.toml)" = "$(grep --max-count 1 version Cargo.lock)"
+find src/ -name "*.rs" -exec touch {} \;
 rustup run nightly cargo clippy -- -W filter_map -W indexing_slicing -W if_not_else -W items_after_statements -W mut_mut -W non_ascii_literal -W nonminimal_bool -W option_map_unwrap_or -W option_map_unwrap_or_else -W option_unwrap_used -W pub_enum_variant_names -W result_unwrap_used -W shadow_reuse -W shadow_same -W shadow_unrelated -W similar_names -W single_match_else -W string_add -W string_add_assign -W stutter -W unicode_not_nfc -W unseparated_literal_suffix -W use_debug -W used_underscore_binding -W wrong_pub_self_convention

src/dom/parser.rs

@@ -183,15 +183,15 @@ fn get_text(h: &Handle) -> Option<String> {
     }
 
     // adjust extracted text: mainly remove white space and some unicode characters
-    if !text_tokens.is_empty() {
+    if text_tokens.is_empty() {
+        None
+    } else {
         Some(String::from(text_tokens.join(" ").trim())
                  .replace("\u{a0}", "")
                  .replace(" >", ">")
                  .replace(" <", "<")
                  .replace(" ::", "::")
                  .replace(":: ", "::")
                  .replace("  ", " "))
-    } else {
-        None
     }
 }