runtime(java): Improve the recognition of the "style" method declarations

- Request the new regexp engine (v7.3.970) for [:upper:] and
  [:lower:].

- Recognise declarations of in-line annotated methods.

- Recognise declarations of _strictfp_ methods.

- Establish partial order for method modifiers as shown in
  the MethodModifier production; namely, _public_ and
  friends should be written the leftmost, possibly followed
  by _abstract_ or _default_, or possibly followed by other
  modifiers.

- Stop looking for parameterisable primitive types (void<?>,
  int<Object>, etc., are malformed).

- Stop looking for arrays of _void_.

- Acknowledge the prevailing convention for method names to
  begin with a small letter and for class/interface names to
  begin with a capital letter; and, therefore, desist from
  claiming declarations of enum constants and constructors
  with javaFuncDef.
  Rationale:
    + Constructor is distinct from method:
      * its (overloaded) name is not arbitrary;
      * its return type is implicit;
      * its _throws_ clause depends on indirect vagaries of
        instance (variable) initialisers;
      * its invocation makes other constructors of its type
        hierarchy invoked one by one, concluding with the
        primordial constructor;
      * its explicit invocation, via _this_ or _super_, can
        only appear as the first statement in a constructor
        (not anymore, see JEP 447); else, its _super_ call
        cannot appear in constructors of _record_ or _enum_;
        and neither invocation is allowed for the primordial
        constructor;
      * it is not a member of its class, like initialisers,
        and is never inherited;
      * it is never _abstract_ or _native_.
    + Constructor declarations tend to be few in number and
      merit visual recognition from method declarations.
    + Enum constants define a fixed set of type instances
      and more resemble class variable initialisers.

Note that the code duplicated for @javaFuncParams is written
keeping in mind for g:java_highlight_functions a pending 3rd
variant, which would require none of the :syn-cluster added
groups.

closes: #14620

Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/dumps/java_methods_style_01.dump

@@ -0,0 +1,20 @@
+| +0&#ffffff0@7|A|(|"+0#e000002&|𝕬|"|)+0#0000000&|,| |B|(|"+0#e000002&|𝕭|"|)+0#0000000&|,| |C|(|"+0#e000002&|𝕮|"|)+0#0000000&|,| |D|(|"+0#e000002&|𝕯|"|)+0#0000000&|,| @35
+@8|E|(|"+0#e000002&|𝕰|"|)+0#0000000&|,| |F|(|"+0#e000002&|𝕱|"|)+0#0000000&|,| |G|(|"+0#e000002&|𝕲|"|)+0#0000000&|,| |H|(|"+0#e000002&|𝕳|"|)+0#0000000&|;| @35
+@8|f+0#4040ff13&|i|n|a|l| +0#0000000&|S|t|r|i|n|g| |𝐬|;| @51
+@8|p+0#00e0003&|r|i|v|a|t|e| +0#0000000&|𝓔|(|S|t|r|i|n|g| |𝐬|)| |{+0#00e0e07&| +0#0000000&|t+0#00e0003&|h|i|s|.+0#0000000&|𝐬| |=| |𝐬|;| |}+0#00e0e07&| +0#0000000&@31
+@4|}+0#00e0e07&| +0#0000000&@69
+> @74
+@4|@+0#e000e06&|T|a|r|g|e|t|(+0#0000000&|j|a|v|a|.|l|a|n|g|.|a|n@1|o|t|a|t|i|o|n|.|E|l|e|m|e|n|t|T|y|p|e|.|M|E|T|H|O|D|)| @22
+@4|@+0#e000e06&|j|a|v|a|.|l|a|n|g|.|a|n@1|o|t|a|t|i|o|n|.|R|e|p|e|a|t|a|b|l|e|(+0#0000000&|T|ɐ|g@1|a|b|l|ɘ|s|.|c+0#00e0003&|l|a|s@1|)+0#0000000&| @21
+@4|@+0#00e0003&|i|n|t|e|r|f|a|c|e| +0#0000000&|T|ɐ|g@1|a|b|l|ɘ| @51
+@4|{+0#00e0e07&| +0#0000000&@69
+| +0#00e0e07&@7|S|t|r|i|n|g|[|]| |v|a|l|u|e|(|)| +0#0000000&|d+0#4040ff13&|e|f|a|u|l|t| +0#0000000&|"+0#e000002&@1|;+0#0000000&| @38
+@4|}+0#00e0e07&| +0#0000000&@69
+@75
+@4|@+0#e000e06&|T|a|r|g|e|t|(+0#0000000&|j|a|v|a|.|l|a|n|g|.|a|n@1|o|t|a|t|i|o|n|.|E|l|e|m|e|n|t|T|y|p|e|.|M|E|T|H|O|D|)| @22
+@4|@+0#00e0003&|i|n|t|e|r|f|a|c|e| +0#0000000&|T|ɐ|g@1|a|b|l|ɘ|s| @50
+@4|{+0#00e0e07&| +0#0000000&@69
+| +0#00e0e07&@7|T|ɐ|g@1|a|b|l|ɘ|[|]| |v|a|l|u|e|(|)|;+0#0000000&| @47
+@4|}+0#00e0e07&| +0#0000000&@69
+@75
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