Fix token1/token2 trimming

Motivation

Previous merge requests were made to allow additional spacing before and after parameters, and between list elements. For example, the list a, b would be parsed as [a, b] (using , as input separator), not as [ a, b].

However, if multiple tokens are given (to functions allowing the use of multiple tokens), spaces between tokens are not removed. For example, the following wikitext merges list elements having the same key (as <key1>:<value1>, <key2>:<value2>, …), concatenating the two values:

{{#listmerge:
 | list         = a:1, b:1, a:2, c:1, b:2, a:3, a:4
 | token1       = @fst,@snd
 | token2       = $fst,$snd
 | fieldsep     = :
 | matchpattern = <esc>{{#ifeq: @fst | $fst | yes }}</esc>
 | mergepattern = @fst:@snd$snd
}}

This wikitext is then parsed as a:1234, b:12, c:1.

But if we add additional spaces between the sub-tokens, we no longer get the expected result. For example, using @fst, @snd as token1 would give the @fst and @snd sub-tokens, then mergepattern would not recognize the @snd parameter. Consequently, the result of the parser function would be a:@snd4, b:@snd2, c:1.

Proposed Changes

The tokens are splitted in ParserPowerLists::mergeListByPattern:

				$tokens1 = explode($tokenSep, $token1);
				$tokens2 = explode($tokenSep, $token2);

Since array_map is used in other functions, it could also be used here to trim all sub-tokens:

				$tokens1 = array_map('trim', explode($tokenSep, $token1));
				$tokens2 = array_map('trim', explode($tokenSep, $token2));