replaced "Elemental" with "elemental" in comments

Co-authored-by: Jeremie Vandenplas <jeremie.vandenplas@gmail.com>

Author: aman-godara

src/stdlib_string_type.fypp

@@ -124,15 +124,15 @@ module stdlib_string_type
 
     !> Returns the sentencecase version of the character sequence hold by the input string
     !>
-    !> This method is Elemental and returns a new string_type instance which holds this
+    !> This method is elemental and returns a new string_type instance which holds this
     !> sentencecase character sequence
     interface to_sentence
         module procedure :: to_sentence_string
     end interface to_sentence
 
     !> Reverses the character sequence hold by the input string
     !> 
-    !> This method is Elemental and returns a new string_type instance which holds this
+    !> This method is elemental and returns a new string_type instance which holds this
     !> reverse character sequence
     interface reverse
         module procedure :: reverse_string