docs: fixed broken links (#453)

Co-authored-by: hackerman <[email protected]>

docs/versioned_docs/version-v0.3/concepts/credentials/username-email-password.mdx

@@ -8,7 +8,7 @@ requires an `identifier` (username, email, phone number, ...) and a `password`
 during registration and login.
 
 ORY Kratos hashes the password after registration, password reset, and password
-change using the [Argon2 Hashing Algorithm](../../concepts/security.md#Argon2), the winner of
+change using the [Argon2 Hashing Algorithm](../../concepts/security#Argon2), the winner of
 the (https:/P-H-C/phc-winner-argon2)[Password Hashing Competition (PHC)].
 
 ## Configuration
@@ -51,13 +51,13 @@ identity:
 ```
 
 If you don't know what that means, please read the
-["Concepts: Identity" Chapter](../../concepts/identity-user-model.md).
+["Concepts: Identity" Chapter](../../concepts/identity-user-model).
 
 For a complete reference, defaults, and description please check the
-[Configuration Reference](../../reference/configuration.md).
+[Configuration Reference](../../reference/configuration).
 
 For a better understanding of security implications imposed by Argon2
-Configuration, head over to [Argon2 Security](../security.mdx#argon2).
+Configuration, head over to [Argon2 Security](../security#argon2).
 
 ## Choosing between Username, Email, Phone Number
 
@@ -85,7 +85,7 @@ The email address however represents a unique identifier and personally
 identifiable information (PII). An attacker could for example check if an email
 address (e.g. `[email protected]`) is registered at a site (e.g. an adult
 website) and use that information for blackmail (see
-[Account Enumeration Attacks](../../concepts/security.md#account-enumeration-attacks)).
+[Account Enumeration Attacks](../../concepts/security#account-enumeration-attacks)).
 
 The same considerations apply to using a phone number as the primary
 registration & login identifier.
@@ -117,7 +117,7 @@ You need to decide which route you want to take.
 
 ### Picking the right JSON Schema
 
-When processing an identity and its traits, the method will use [JSON Schema](../../reference/json-schema-json-paths.md)
+When processing an identity and its traits, the method will use [JSON Schema](../../reference/json-schema-json-paths)
 to extract one or more identifiers.
 
 #### Use Case: Email and Password
@@ -287,7 +287,7 @@ Assuming your traits schema is as follows:
 
 And an identity registers with the following JSON payload (more on registration
 in
-[Selfservice Registration](../self-service/flows/user-login-user-registration.md)):
+[Selfservice Registration](../../self-service/flows/user-login-user-registration)):
 
 ```json
 {