en: Fix several -er and -est words (e.g. wickeder, wickedest, brittlest).

dictsource/en_list

 literate	$alt2
 literature	lItrI#tS3
 ?3 literature	lIt3rI#tS3
-littlest	lIt@L@st
 live		laIv          $onlys
 live		lIv           $verb
 (live in)	lIv||I2n
 ?3 modem	moUd@m
 moderate	m0d@reIt      $verb
 modernity	$2
+modest		m0dIst
 mogul		moUg@L
 mohican		moUh'i:k@n
 moi		mwA:

dictsource/en_rules

 .group er
      &) er         3
    @@@) er (_S2de  3         // suffix
+   @ed) er (_S2d   3         // suffix, adjective
+   ied) er (_S2de  3         // suffix
     %C) er (_S3    3
     mm) er (_      3
     rn) er (_S2    3
    &tr) ess (_     @s
   dist) ess (_     Es
      &) es (y_     @s
-     &) es (t_     I2s
-    Cr) es (t      Es
+     &) est (_S3e  I2st
+   &ng) est (_S3   gI2st	// ng = /N/
+  &ang) est (_S3e  I2st		// ng = /dZ/
+  &eur) est (_S3   I2st
+ inter) est        Est
+    Cr) es (t+     Es
     gu) es (t_     Es
         es (tral_  'Es
      v) es (t+     Es
         l (E       l
         lle (_     l
     %C) l (eC_     l
+    %C) l (est_    l
   @@ba) lled (_S2v d
     @@) lled (_S3v d
      B) l (_       @L
     gi) ng (er     ndZ
      o) ng (er     Ng
    you) ng (er     Ng
-        ng (est    Ng
     co) nge (st    ndZE
    cri) nging      ndZI2N
     hi) nging      ndZI2N
         ther (er   D3
         th (erC    D
         there (_   D3        // thering
-        th (est    D
+        thest      DI2st     // farthest, furthest
     ea) th (er     D
      n) th (er+    T
         therap     TEr@p

src/libespeak-ng/dictionary.c

 	static const char *add_e_additions[] = {
 		"c", "rs", "ir", "ur", "ath", "ns", "u",
 		"spong", // sponge
+		"rang", // strange
+		"larg", // large
 		NULL
 	};