BREAKING: update mautrix to 0.15.x

vendor/golang.org/x/net/html/doc.go

@@ -92,6 +92,27 @@ example, to process each anchor node in depth-first order:
 The relevant specifications include:
 https://html.spec.whatwg.org/multipage/syntax.html and
 https://html.spec.whatwg.org/multipage/syntax.html#tokenization
+
+# Security Considerations
+
+Care should be taken when parsing and interpreting HTML, whether full documents
+or fragments, within the framework of the HTML specification, especially with
+regard to untrusted inputs.
+
+This package provides both a tokenizer and a parser, which implement the
+tokenization, and tokenization and tree construction stages of the WHATWG HTML
+parsing specification respectively. While the tokenizer parses and normalizes
+individual HTML tokens, only the parser constructs the DOM tree from the
+tokenized HTML, as described in the tree construction stage of the
+specification, dynamically modifying or extending the docuemnt's DOM tree.
+
+If your use case requires semantically well-formed HTML documents, as defined by
+the WHATWG specification, the parser should be used rather than the tokenizer.
+
+In security contexts, if trust decisions are being made using the tokenized or
+parsed content, the input must be re-serialized (for instance by using Render or
+Token.String) in order for those trust decisions to hold, as the process of
+tokenization or parsing may alter the content.
 */
 package html // import "golang.org/x/net/html"