Editorial: Standardize the spelling of "uppercase" and "lowercase"

Matches Unicode:
* https://unicode.org/glossary/
* http://www.unicode.org/reports/tr18/
* http://www.unicode.org/unicode/reports/tr21
* https://www.unicode.org/reports/tr31

Ref tc39/ecma262#2598

spec/locale-sensitive-functions.html

@@ -68,13 +68,13 @@ <h1>String.prototype.toLocaleLowerCase ( [ _locales_ ] )</h1>
         1. Let _locale_ be BestAvailableLocale(_availableLocales_, _noExtensionsLocale_).
         1. If _locale_ is *undefined*, let _locale_ be *"und"*.
         1. Let _cpList_ be a List containing in order the code points of _S_ as defined in es2022, <emu-xref href="#sec-ecmascript-language-types-string-type"></emu-xref>, starting at the first element of _S_.
-        1. Let _cuList_ be a List where the elements are the result of a lower case transformation of the ordered code points in _cpList_ according to the Unicode Default Case Conversion algorithm or an implementation-defined conversion algorithm. A conforming implementation's lower case transformation algorithm must always yield the same _cpList_ given the same _cuList_ and locale.
+        1. Let _cuList_ be a List where the elements are the result of a lowercase transformation of the ordered code points in _cpList_ according to the Unicode Default Case Conversion algorithm or an implementation-defined conversion algorithm. A conforming implementation's lowercase transformation algorithm must always yield the same _cpList_ given the same _cuList_ and locale.
         1. Let _L_ be a String whose elements are the UTF-16 Encoding (defined in es2022, <emu-xref href="#sec-ecmascript-language-types-string-type"></emu-xref>) of the code points of _cuList_.
         1. Return _L_.
       </emu-alg>
 
       <p>
-        Lower case code point mappings may be derived according to a tailored version of the Default Case Conversion Algorithms of the Unicode Standard. Implementations may use locale specific tailoring defined in SpecialCasings.txt and/or CLDR and/or any other custom tailoring.
+        Lowercase code point mappings may be derived according to a tailored version of the Default Case Conversion Algorithms of the Unicode Standard. Implementations may use locale specific tailoring defined in SpecialCasings.txt and/or CLDR and/or any other custom tailoring.
       </p>
 
       <emu-note>
@@ -94,7 +94,7 @@ <h1>String.prototype.toLocaleUpperCase ( [ _locales_ ] )</h1>
       </p>
 
       <p>
-        This function interprets a String value as a sequence of code points, as described in es2022, <emu-xref href="#sec-ecmascript-language-types-string-type"></emu-xref>. This function behaves in exactly the same way as `String.prototype.toLocaleLowerCase`, except that characters are mapped to their _uppercase_ equivalents. A conforming implementation's upper case transformation algorithm must always yield the same result given the same sequence of code points and locale.
+        This function interprets a String value as a sequence of code points, as described in es2022, <emu-xref href="#sec-ecmascript-language-types-string-type"></emu-xref>. This function behaves in exactly the same way as `String.prototype.toLocaleLowerCase`, except that characters are mapped to their _uppercase_ equivalents. A conforming implementation's uppercase transformation algorithm must always yield the same result given the same sequence of code points and locale.
       </p>
 
       <emu-note>

spec/locales-currencies-tz.html

@@ -136,7 +136,7 @@ <h1>DefaultLocale ( )</h1>
     <h1>Currency Codes</h1>
 
     <p>
-      The ECMAScript 2022 Internationalization API Specification identifies currencies using 3-letter currency codes as defined by ISO 4217. Their canonical form is upper case.
+      The ECMAScript 2022 Internationalization API Specification identifies currencies using 3-letter currency codes as defined by ISO 4217. Their canonical form is uppercase.
     </p>
 
     <p>

spec/numberformat.html

@@ -122,7 +122,7 @@ <h1>InitializeNumberFormat ( _numberFormat_, _locales_, _options_ )</h1>
       <h1>CurrencyDigits ( _currency_ )</h1>
 
       <p>
-        When the CurrencyDigits abstract operation is called with an argument _currency_ (which must be an upper case String value), the following steps are taken:
+        When the CurrencyDigits abstract operation is called with an argument _currency_ (which must be an uppercase String value), the following steps are taken:
       </p>
 
       <emu-alg>