Add documentation for JavaScript String trimStart() method (#7703)

* Added new Term Entry (trimStart)

* minor fixes

* Format

---------

Author: Tia-ani

content/javascript/concepts/strings/terms/trimStart/trimStart.md

@@ -0,0 +1,81 @@
+---
+Title: '.trimStart()'
+Description: 'Removes whitespace characters from the start (left side) of a string.'
+Subjects:
+  - 'Computer Science'
+  - 'Web Development'
+Tags:
+  - 'Methods'
+  - 'Strings'
+CatalogContent:
+  - 'introduction-to-javascript'
+  - 'paths/front-end-engineer-career-path'
+---
+
+The **`trimStart()`** method removes whitespace characters from the beginning of a string. It returns a new string with leading whitespace removed, leaving the original string unchanged. This method is also available as `trimLeft()`, which is an alias for `trimStart()`.
+
+Whitespace characters include spaces, tabs, line breaks, and other Unicode whitespace characters.
+
+## Syntax
+
+```pseudo
+string.trimStart()
+```
+
+**Parameters:**
+
+The `trimStart()` method does not take any parameters.
+
+**Return value:**
+
+Returns a new string with whitespace removed from the beginning of the original string. The original string remains unchanged.
+
+## Example
+
+The following example demonstrates how `trimStart()` removes leading whitespace:
+
+```js
+const greeting = '   Hello, World!';
+const trimmedGreeting = greeting.trimStart();
+
+console.log(greeting);
+console.log(trimmedGreeting);
+console.log(greeting.length);
+console.log(trimmedGreeting.length);
+```
+
+The output of this code is:
+
+```shell
+   Hello, World!
+Hello, World!
+16
+13
+```
+
+In this example, `trimStart()` removes the three leading spaces from the string, reducing its length from 16 to 13 characters.
+
+## Codebyte Example
+
+Run the following code to see `trimStart()` in action:
+
+```codebyte/javascript
+// Example with various whitespace characters
+const text1 = "   JavaScript";
+const text2 = "\t\tProgramming";
+const text3 = "\n\nCoding";
+
+console.log("Original:", text1);
+console.log("Trimmed:", text1.trimStart());
+
+console.log("Original:", text2);
+console.log("Trimmed:", text2.trimStart());
+
+console.log("Original:", text3);
+console.log("Trimmed:", text3.trimStart());
+
+// Example showing that trailing spaces are preserved
+const text4 = "   Both sides   ";
+console.log("Original length:", text4.length);
+console.log("After trimStart length:", text4.trimStart().length);
+```