added some default text to the editor

i couldn't do this before, because i didn't know how to make Blazor react to the pre-set text (located at `Index.razor:11`) upon page load. i searched and found some overridable Blazor functions that might help. the "on initialize" function occurs too soon; the default text isn't accessible yet. the "on after render" function is what i needed; it occurs a bit later in the Blazor lifecycle, allowing the overlay to update using the pre-set `textarea` content.

we also have a minor rule change with the `---` lines: you may now include spaces/tabs immediately following the `-` dashes.

and lastly, a fix: the regular expression for the "mono" formatting (the `\`` via back-tick character) was incorrect. when searching for content between the two back-ticks, the pattern was excluding the `_` underscore character, but it should have excluded the back-tick. a classic _copy-paste_ bug: i copied from the "italic" pattern, but failed to make all the necessary changes to the duplicated code.

typing ``` above made me realize that the pattern did _not_ handle that scenario. i started trying to fix this by allowing the content between back-ticks to be a single back-tick. however, three consecutive back-ticks is meant to be the start of "multiline mono" formatting. and the fix still doesn't address the next problem: how do i show _two_ back-ticks in a "mono" black? i think the solution will be to "escape" the inner back-ticks  using a `\` backslash character as a prefix (for example: `\``). this does not seem like an important issue. i am naturally driven to fix it anyway, but it's more important to prioritize and stay on track. i'll document it as a known issue.

solution/Poemdown.Blaze/Pages/Index.razor

@@ -7,7 +7,21 @@
 	<div class="row">
 		<div class="editor col-12 col-sm-6">
 			<textarea class="monospace" @oninput="HandleInput" @onkeydown="HandleKeyDown"
-				placeholder="just begin."></textarea>
+				placeholder="just begin.">
+does _this_ actually *work*?
+
+---
+
+# test single
+more things
+e	v	e		n more
+
+## test double
+something else
+
+### test triple
+this is the `testing` code`
+			</textarea>
 			<div class="overlay monospace"></div>
 		</div>
 		<div class="preview col-12 col-sm-6">
@@ -20,15 +34,25 @@
 
 	private string previousInput = "";
 
-	private void HandleKeyDown(KeyboardEventArgs args) {
-		UpdateOverlay();
+	/*protected override async Task OnInitializedAsync() {
+		await UpdateOverlay(); //too soon; _wait_
+	}*/
+
+	protected override async Task OnAfterRenderAsync(bool isFirstRender) {
+		if ( isFirstRender ) {
+			await UpdateOverlay();
+		}
+}
+
+	private async void HandleKeyDown(KeyboardEventArgs args) {
+		await UpdateOverlay();
 	}
 
-	private void HandleInput(ChangeEventArgs args) {
-		UpdateOverlay();
+	private async void HandleInput(ChangeEventArgs args) {
+		await UpdateOverlay();
 	}
 
-	private async void UpdateOverlay() {
+	private async Task UpdateOverlay() {
 		string input = await JS.InvokeAsync<string>("getEditorTextareaValue");
 
 		if ( input == previousInput ) {

solution/Poemdown.Console/Program.cs

@@ -1,7 +1,7 @@
-const string sampleText = @"
+const string sampleText = @"
 does _this_ actually *work*?
 
----
+---   
 
 # test single
 more things
@@ -11,7 +11,7 @@ more things
 something else
 
 ### test triple
-
+what about ``` then
 this is the `testing` code
 ";
 

solution/Poemdown.Core/Convert.cs

@@ -19,8 +19,8 @@ public static class Convert {
 		html = Regex.Replace(html, @"\r", "");
 		html = Regex.Replace(html, @"(\*)([^\*\n]+)(\*)", "<b><c>$1</c>$2<c>$3</c></b>");
 		html = Regex.Replace(html, @"(_)([^_\n]+)(_)", "<em><c>$1</c>$2<c>$3</c></em>");
-		html = Regex.Replace(html, @"(`)([^_\n]+)(`)", "<mono><c>$1</c>$2<c>$3</c></mono>");
-		html = Regex.Replace(html, @"(^|\n)(---)($|\n)", "$1<line><c>$2</c></line><hr/>");
+		html = Regex.Replace(html, @"(`)([^`\n]+|`)(`)", "<mono><c>$1</c>$2<c>$3</c></mono>");
+		html = Regex.Replace(html, @"(^|\n)(---)([ \t]*)($|\n)","$1<line><c>$2</c></line>$3<hr/>");
 		html = Regex.Replace(html, @"(^|\n)(#)(\s+[^$\n]+)", "$1<head1><c>$2</c>$3</head1>");
 		html = Regex.Replace(html, @"(^|\n)(##)(\s+[^$\n]+)", "$1<head2><c>$2</c>$3</head2>");
 		html = Regex.Replace(html, @"(^|\n)(###)(\s+[^$\n]+)", "$1<head3><c>$2</c>$3</head3>");