feat: support line number checking in link fragment (e.g: '#L50')

Fixes #6

test/fixtures/valid/existing-heading-case-insensitive/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+## Existing Heading

test/fixtures/valid/existing-heading-case-insensitive/existing-heading-case-insensitive.md

@@ -0,0 +1,3 @@
+# Valid
+
+[Link fragment](./awesome.md#ExistIng-Heading)

test/fixtures/valid/existing-heading-fragment/awesome.md

@@ -1,4 +1,4 @@
-# Valid
+# Awesome
 
 ## Existing Heading
 

test/fixtures/valid/valid-heading-like-number-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+## L7

test/fixtures/valid/valid-heading-like-number-fragment/valid-heading-like-number-fragment.md

@@ -0,0 +1,3 @@
+# Valid
+
+[Link fragment](./awesome.md#L7)

test/fixtures/valid/valid-line-number-fragment/awesome.md

@@ -0,0 +1,9 @@
+# Awesome
+
+ABC
+
+Line 5
+
+Line 7 Text
+
+## L7

test/fixtures/valid/valid-line-number-fragment/valid-line-number-fragment.md

@@ -0,0 +1,3 @@
+# Valid
+
+[Link fragment line number 7](./awesome.md#L7)