Auto merge of #13969 - bbansalWolfPack:master, r=jdm

html form validation initial steps with  test html file

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Added code for initial steps in html form validation.
1. Added methods for trait validatable
2. implemented stub methods for  elements like HTMLInputElement, HTMLButtonElement, etc

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- [ X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/dom/validitystate.rs

@@ -26,6 +26,21 @@ pub enum ValidityStatus {
     Valid
 }
 
+bitflags!{
+    pub flags ValidationFlags: u32 {
+        const VALUE_MISSING    = 0b0000000001,
+        const TYPE_MISMATCH    = 0b0000000010,
+        const PATTERN_MISMATCH = 0b0000000100,
+        const TOO_LONG         = 0b0000001000,
+        const TOO_SHORT        = 0b0000010000,
+        const RANGE_UNDERFLOW  = 0b0000100000,
+        const RANGE_OVERFLOW   = 0b0001000000,
+        const STEP_MISMATCH    = 0b0010000000,
+        const BAD_INPUT        = 0b0100000000,
+        const CUSTOM_ERROR     = 0b1000000000,
+    }
+}
+
 // https://html.spec.whatwg.org/multipage/#validitystate
 #[dom_struct]
 pub struct ValidityState {