Remove ${project.basedir}/ from source root dir paths in Maven documentation examples

Author: PetrakovichVictoria

docs/topics/maven.md

@@ -86,8 +86,8 @@ To compile source code, specify the source directories in the `<build>` tag:
 
 ```xml
 <build>
-    <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
-    <testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
+    <sourceDirectory>src/main/kotlin</sourceDirectory>
+    <testSourceDirectory>src/test/kotlin</testSourceDirectory>
 </build>
 ```
 
@@ -157,8 +157,8 @@ making sure that the `kotlin` plugin comes before the `maven-compiler-plugin` in
                     </goals>
                     <configuration>
                         <sourceDirs>
-                            <sourceDir>${project.basedir}/src/main/kotlin</sourceDir>
-                            <sourceDir>${project.basedir}/src/main/java</sourceDir>
+                            <sourceDir>src/main/kotlin</sourceDir>
+                            <sourceDir>src/main/java</sourceDir>
                         </sourceDirs>
                     </configuration>
                 </execution>
@@ -170,8 +170,8 @@ making sure that the `kotlin` plugin comes before the `maven-compiler-plugin` in
                     </goals>
                     <configuration>
                         <sourceDirs>
-                            <sourceDir>${project.basedir}/src/test/kotlin</sourceDir>
-                            <sourceDir>${project.basedir}/src/test/java</sourceDir>
+                            <sourceDir>src/test/kotlin</sourceDir>
+                            <sourceDir>src/test/java</sourceDir>
                         </sourceDirs>
                     </configuration>
                 </execution>