minor #17896 Changing "white spaces" => "whitespace" (ThomasLandauer)

This PR was squashed before being merged into the 5.4 branch.

Discussion
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Changing "white spaces" => "whitespace"

According to twigphp/Twig#3806 (comment) - but I didn't doublecheck.

Commits
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369b563 Changing "white spaces" => "whitespace"

components/string.rst

@@ -177,8 +177,8 @@ There is also a method to get the bytes stored at some position::
     b('नमस्ते')->bytesAt(1);   // [164]
     u('नमस्ते')->bytesAt(1);   // [224, 164, 174]
 
-Methods Related to Length and White Spaces
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Methods Related to Length and Whitespace Characters
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 ::
 
@@ -202,13 +202,13 @@ Methods Related to Length and White Spaces
     END";
     u($text)->width(); // 14
 
-    // only returns TRUE if the string is exactly an empty string (not even white spaces)
+    // only returns TRUE if the string is exactly an empty string (not even whitespace)
     u('hello world')->isEmpty();  // false
     u('     ')->isEmpty();        // false
     u('')->isEmpty();             // true
 
-    // removes all white spaces from the start and end of the string and replaces two
-    // or more consecutive white spaces inside contents by a single white space
+    // removes all whitespace from the start and end of the string and replaces two
+    // or more consecutive whitespace characters inside contents by a single white space
     u("  \n\n   hello        world \n    \n")->collapseWhitespace(); // 'hello world'
 
 Methods to Change Case
@@ -298,7 +298,7 @@ Methods to Pad and Trim
     // repeats the given string the number of times passed as argument
     u('_.')->repeat(10); // '_._._._._._._._._._.'
 
-    // removes the given characters (by default, white spaces) from the string
+    // removes the given characters (default: whitespace characters) from the beginning and end of a string
     u('   Lorem Ipsum   ')->trim(); // 'Lorem Ipsum'
     u('Lorem Ipsum   ')->trim('m'); // 'Lorem Ipsum   '
     u('Lorem Ipsum')->trim('m');    // 'Lorem Ipsu'