[SPARK-50987][DOCS] Make spark-connect-overview.mds version strings up-to-date

### What changes were proposed in this pull request?

This PR aims to make `spark-connect-overview.md`'s version strings up-to-date.

### Why are the changes needed?

- https://apache.github.io/spark/spark-connect-overview.html

**BEFORE**

<img width="477" alt="Screenshot 2025-01-24 at 11 17 03 PM" src="https://github.com/user-attachments/assets/4ee91119-e116-4573-8446-32bf18342ac5" />

**AFTER**
<img width="318" alt="Screenshot 2025-01-24 at 11 17 22 PM" src="https://github.com/user-attachments/assets/9e3f9061-6623-440f-8031-5ee85666675c" />

**BEFORE**
<img width="546" alt="Screenshot 2025-01-24 at 11 17 58 PM" src="https://github.com/user-attachments/assets/dc3ac80b-a5fc-4ea2-bf1d-4025a6ae204f" />

**AFTER**
<img width="552" alt="Screenshot 2025-01-24 at 11 18 35 PM" src="https://github.com/user-attachments/assets/8c5fe8cf-a8b1-4933-a593-3037f356c81a" />

**BEFORE**
<img width="679" alt="Screenshot 2025-01-24 at 11 21 33 PM" src="https://github.com/user-attachments/assets/d4d69efe-2fb4-43ea-be13-0d1bbe251b2c" />

**AFTER**
<img width="674" alt="Screenshot 2025-01-24 at 11 22 29 PM" src="https://github.com/user-attachments/assets/09a413fe-3659-4bba-b37c-609f2d6f16ba" />

### Does this PR introduce _any_ user-facing change?

This keeps the document up-to-date for Apache Spark 3.5.5/4.0.0+.

### How was this patch tested?

Manual review.

### Was this patch authored or co-authored using generative AI tooling?
No

Closes #49665 from dongjoon-hyun/SPARK-50987.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

docs/spark-connect-overview.md

@@ -284,11 +284,11 @@ The connection may also be programmatically created using _SparkSession#builder_
 
 <div data-lang="python"  markdown="1">
 
-First, install PySpark with `pip install pyspark[connect]==3.5.0` or if building a packaged PySpark application/library,
+First, install PySpark with `pip install pyspark[connect]=={{site.SPARK_VERSION_SHORT}}` or if building a packaged PySpark application/library,
 add it your setup.py file as:
 {% highlight python %}
 install_requires=[
-'pyspark[connect]==3.5.0'
+'pyspark[connect]=={{site.SPARK_VERSION_SHORT}}'
 ]
 {% endhighlight %}
 
@@ -335,7 +335,7 @@ Lines with a: 72, lines with b: 39
 To use Spark Connect as part of a Scala application/project, we first need to include the right dependencies.
 Using the `sbt` build system as an example, we add the following dependencies to the `build.sbt` file:
 {% highlight sbt %}
-libraryDependencies += "org.apache.spark" %% "spark-connect-client-jvm" % "3.5.0"
+libraryDependencies += "org.apache.spark" %% "spark-connect-client-jvm" % "{{site.SPARK_VERSION_SHORT}}"
 {% endhighlight %}
 
 When writing your own code, include the `remote` function with a reference to
@@ -380,9 +380,9 @@ HTTP/2 interface allows for the use of authenticating proxies, which makes
 it possible to secure Spark Connect without having to implement authentication
 logic in Spark directly.
 
-# What is supported in Spark 3.4
+# What is supported
 
-**PySpark**: In Spark 3.4, Spark Connect supports most PySpark APIs, including
+**PySpark**: Since Spark 3.4, Spark Connect supports most PySpark APIs, including
 [DataFrame](api/python/reference/pyspark.sql/dataframe.html),
 [Functions](api/python/reference/pyspark.sql/functions.html), and
 [Column](api/python/reference/pyspark.sql/column.html). However,
@@ -393,7 +393,7 @@ supported in the [API reference](api/python/reference/index.html) documentation.
 Supported APIs are labeled "Supports Spark Connect" so you can check whether the
 APIs you are using are available before migrating existing code to Spark Connect.
 
-**Scala**: In Spark 3.5, Spark Connect supports most Scala APIs, including
+**Scala**: Since Spark 3.5, Spark Connect supports most Scala APIs, including
 [Dataset](api/scala/org/apache/spark/sql/Dataset.html),
 [functions](api/scala/org/apache/spark/sql/functions$.html),
 [Column](api/scala/org/apache/spark/sql/Column.html),