Revert change: zero-width spaces are not spaces

In case, it's better to deal with them in `processTerm` as a
normalization.

CHANGELOG.md

@@ -8,7 +8,6 @@
     invalid operators at compile time.
   - More informative error when specifying an invalid value for `combineWith`
     in JavaScript (in TypeScript this would be a compile time error)
-  - Consider also Unicode zero-width spaces as separators in the tokenizer
   - Use the Unicode flag to simplify the tokenizer regular expression
 
 ## v6.3.0 - 2023-11-22

src/MiniSearch.test.js

@@ -1682,7 +1682,7 @@ e forse del mio dir poco ti cale`
         },
         {
           id: 2,
-          text: 'The estimates range from roughly 1 in 100 to 1 in 100,000. The higher figures come from the working engineers, and the very low figures from management. What are the causes and consequences of this lack of \u200Bagreement? Since 1 part in 100,000 would imply that one could put a Shuttle up each day for 300 years expecting to lose only one, we could properly ask "What is the cause of management\'s fantastic faith in the machinery?"'
+          text: 'The estimates range from roughly 1 in 100 to 1 in 100,000. The higher figures come from the working engineers, and the very low figures from management. What are the causes and consequences of this lack of agreement? Since 1 part in 100,000 would imply that one could put a Shuttle up each day for 300 years expecting to lose only one, we could properly ask "What is the cause of management\'s fantastic faith in the machinery?"'
         }
       ]
       const ms = new MiniSearch({ fields: ['text'] })
@@ -1693,7 +1693,6 @@ e forse del mio dir poco ti cale`
 
       expect(ms.search('300').length).toBeGreaterThan(0)
       expect(ms.search('machinery').length).toBeGreaterThan(0)
-      expect(ms.search('agreement').length).toBeGreaterThan(0)
     })
 
     it('supports non-latin alphabets', () => {

src/MiniSearch.ts

@@ -2032,6 +2032,6 @@ const objectToNumericMap = <T>(object: { [key: string]: T }): Map<number, T> =>
   return map
 }
 
-// This regular expression matches any Unicode space (including zero-width
-// spaces \u200B-\u200D and \uFEFF), newline, or punctuation character
-const SPACE_OR_PUNCTUATION = /[\n\r\p{Z}\p{P}\u200B-\u200D\uFEFF]/u
+// This regular expression matches any Unicode space, newline, or punctuation
+// character
+const SPACE_OR_PUNCTUATION = /[\n\r\p{Z}\p{P}]/u