Improve various Vim syntax highlighting things.
Improve various Vim syntax highlighting things.

- Implement comment nesting (the implementation is quite ugly at present
  and is not quite correct; note the big comment in that area).

- Highlight invalid escape sequences as errors.

- Fix up various inconsistencies and incorrectnesses in number
  highlighting.

- Update prelude items (``std::io::{Buffer, Writer, Reader, Seek}``).

- Highlight the ``proc`` keyword.

- Remove %-formatting sequence highlighting (a relic of old formatting).

- Don't highlight TODO in strings (it's unconventional).

AerialX/rust,dinfuehr/rust,defuz/rust,robertg/rust,AerialX/rust,michaelballantyne/rust-gpu,miniupnp/rust,kwantam/rust,SiegeLord/rust,miniupnp/rust,graydon/rust,nham/rust,ruud-v-a/rust,emk/rust,untitaker/rust,mihneadb/rust,dwillmer/rust,mahkoh/rust,emk/rust,richo/rust,michaelballantyne/rust-gpu,ejjeong/rust,richo/rust,erickt/rust,andars/rust,cllns/rust,rohitjoshi/rust,fabricedesre/rust,jbclements/rust,omasanori/rust,servo/rust,zubron/rust,ebfull/rand,richo/rust,andars/rust,jroesch/rust,dwillmer/rust,krzysz00/rust,mitsuhiko/rust,rprichard/rust,fabricedesre/rust,mdinger/rust,graydon/rust,nwin/rust,zachwick/rust,aturon/rust,mvdnes/rust,bhickey/rand,rohitjoshi/rust,vhbit/rust,dwillmer/rust,mahkoh/rust,0x73/rust,krzysz00/rust,jbclements/rust,pshc/rust,dinfuehr/rust,mitsuhiko/rust,emk/rust,quornian/rust,pythonesque/rust,bombless/rust,Ryman/rust,sae-bom/rust,defuz/rust,l0kod/rust,avdi/rust,l0kod/rust,seanrivera/rust,kwantam/rust,cllns/rust,ruud-v-a/rust,l0kod/rust,XMPPwocky/rust,servo/rust,nham/rust,ejjeong/rust,P1start/rust,P1start/rust,mahkoh/rust,bombless/rust,sae-bom/rust,kimroen/rust,nwin/rust,mitsuhiko/rust,ktossell/rust,aidancully/rust,AerialX/rust-rt-minimal,bluss/rand,philyoon/rust,stepancheg/rust-ide-rust,michaelballantyne/rust-gpu,erickt/rust,rohitjoshi/rust,omasanori/rust,TheNeikos/rust,emk/rust,quornian/rust,zaeleus/rust,zaeleus/rust,jbclements/rust,sae-bom/rust,omasanori/rust,emk/rust,aturon/rust,dinfuehr/rust,hauleth/rust,zubron/rust,victorvde/rust,kimroen/rust,ktossell/rust,SiegeLord/rust,jroesch/rust,aepsil0n/rust,nham/rust,AerialX/rust-rt-minimal,SiegeLord/rust,AerialX/rust-rt-minimal,defuz/rust,mihneadb/rust,cllns/rust,hauleth/rust,quornian/rust,graydon/rust,mvdnes/rust,robertg/rust,aturon/rust,pelmers/rust,ejjeong/rust,pythonesque/rust,carols10cents/rust,TheNeikos/rust,jbclements/rust,aneeshusa/rust,hauleth/rust,zaeleus/rust,zaeleus/rust,bombless/rust-docs-chinese,krzysz00/rust,victorvde/rust,andars/rust,SiegeLord/rust,gifnksm/rust,gifnksm/rust,quornian/rust,avdi/rust,pythonesque/rust,untitaker/rust,mdinger/rust,XMPPwocky/rust,KokaKiwi/rust,miniupnp/rust,krzysz00/rust,mahkoh/rust,ejjeong/rust,miniupnp/rust,stepancheg/rust-ide-rust,erickt/rust,untitaker/rust,stepancheg/rust-ide-rust,GBGamer/rust,ebfull/rust,Ryman/rust,l0kod/rust,ruud-v-a/rust,zachwick/rust,P1start/rust,mdinger/rust,pczarn/rust,kwantam/rust,stepancheg/rust-ide-rust,jashank/rust,ejjeong/rust,avdi/rust,vhbit/rust,ebfull/rust,dwillmer/rust,bombless/rust,erickt/rust,KokaKiwi/rust,AerialX/rust-rt-minimal,AerialX/rust-rt-minimal,hauleth/rust,0x73/rust,kwantam/rust,barosl/rust,andars/rust,ebfull/rust,jbclements/rust,jroesch/rust,pshc/rust,servo/rust,ktossell/rust,GBGamer/rust,jbclements/rust,mvdnes/rust,bombless/rust,untitaker/rust,mvdnes/rust,untitaker/rust,nwin/rust,l0kod/rust,miniupnp/rust,dwillmer/rust,pelmers/rust,barosl/rust,carols10cents/rust,barosl/rust,pelmers/rust,zubron/rust,sae-bom/rust,Ryman/rust,ktossell/rust,ktossell/rust,zubron/rust,dwillmer/rust,aidancully/rust,zachwick/rust,jbclements/rust,jashank/rust,pelmers/rust,zaeleus/rust,rprichard/rust,aepsil0n/rust,Ryman/rust,miniupnp/rust,victorvde/rust,jashank/rust,AerialX/rust,nham/rust,sae-bom/rust,cllns/rust,GBGamer/rust,mitsuhiko/rust,richo/rust,mihneadb/rust,jashank/rust,pczarn/rust,mahkoh/rust,aidancully/rust,philyoon/rust,rprichard/rust,carols10cents/rust,zubron/rust,seanrivera/rust,kimroen/rust,victorvde/rust,philyoon/rust,mitsuhiko/rust,servo/rust,dinfuehr/rust,nwin/rust,avdi/rust,philyoon/rust,carols10cents/rust,kwantam/rust,jbclements/rust,nham/rust,mahkoh/rust,seanrivera/rust,SiegeLord/rust,victorvde/rust,philyoon/rust,omasanori/rust,kimroen/rust,kimroen/rust,quornian/rust,TheNeikos/rust,krzysz00/rust,kimroen/rust,reem/rust,cllns/rust,ktossell/rust,fabricedesre/rust,ruud-v-a/rust,robertg/rust,hauleth/rust,fabricedesre/rust,gifnksm/rust,KokaKiwi/rust,rprichard/rust,pelmers/rust,pythonesque/rust,miniupnp/rust,carols10cents/rust,omasanori/rust,erickt/rust,mdinger/rust,shepmaster/rand,pshc/rust,jroesch/rust,jashank/rust,pczarn/rust,aneeshusa/rust,pczarn/rust,jroesch/rust,michaelballantyne/rust-gpu,GBGamer/rust,XMPPwocky/rust,kimroen/rust,mihneadb/rust,vhbit/rust,defuz/rust,mvdnes/rust,pczarn/rust,kwantam/rust,aturon/rust,barosl/rust,mihneadb/rust,andars/rust,carols10cents/rust,gifnksm/rust,stepancheg/rust-ide-rust,nwin/rust,waynenilsen/rand,aidancully/rust,aturon/rust,servo/rust,SiegeLord/rust,l0kod/rust,jroesch/rust,andars/rust,aepsil0n/rust,mitsuhiko/rust,fabricedesre/rust,P1start/rust,AerialX/rust,GBGamer/rust,michaelballantyne/rust-gpu,vhbit/rust,aidancully/rust,aturon/rust,AerialX/rust,barosl/rust,mdinger/rust,P1start/rust,GBGamer/rust,richo/rust,emk/rust,vhbit/rust,GBGamer/rust,0x73/rust,arthurprs/rand,pythonesque/rust,reem/rust,barosl/rust,nham/rust,gifnksm/rust,reem/rust,hauleth/rust,quornian/rust,ktossell/rust,achanda/rand,XMPPwocky/rust,nwin/rust,pczarn/rust,ebfull/rust,Ryman/rust,XMPPwocky/rust,jbclements/rust,rprichard/rust,michaelballantyne/rust-gpu,P1start/rust,vhbit/rust,P1start/rust,KokaKiwi/rust,Ryman/rust,bombless/rust,zubron/rust,servo/rust,victorvde/rust,zachwick/rust,untitaker/rust,zachwick/rust,l0kod/rust,seanrivera/rust,nwin/rust,ebfull/rust,vhbit/rust,rohitjoshi/rust,sae-bom/rust,aidancully/rust,nham/rust,zaeleus/rust,aneeshusa/rust,emk/rust,robertg/rust,dwillmer/rust,huonw/rand,dinfuehr/rust,TheNeikos/rust,dinfuehr/rust,philyoon/rust,jashank/rust,0x73/rust,aneeshusa/rust,erickt/rust,ejjeong/rust,pshc/rust,erickt/rust,rprichard/rust,TheNeikos/rust,pelmers/rust,aneeshusa/rust,l0kod/rust,0x73/rust,quornian/rust,jroesch/rust,aneeshusa/rust,SiegeLord/rust,robertg/rust,ebfull/rust,avdi/rust,pshc/rust,defuz/rust,mihneadb/rust,mitsuhiko/rust,servo/rust,aepsil0n/rust,aturon/rust,krzysz00/rust,graydon/rust,mvdnes/rust,pshc/rust,XMPPwocky/rust,rohitjoshi/rust,fabricedesre/rust,TheNeikos/rust,richo/rust,seanrivera/rust,robertg/rust,fabricedesre/rust,graydon/rust,reem/rust,pshc/rust,zubron/rust,miniupnp/rust,seanrivera/rust,jroesch/rust,reem/rust,GBGamer/rust,pczarn/rust,zachwick/rust,0x73/rust,aepsil0n/rust,0x73/rust,dwillmer/rust,gifnksm/rust,AerialX/rust-rt-minimal,GrahamDennis/rand,reem/rust,defuz/rust,stepancheg/rust-ide-rust,michaelballantyne/rust-gpu,AerialX/rust,Ryman/rust,ruud-v-a/rust,KokaKiwi/rust,rohitjoshi/rust,jashank/rust,bombless/rust,stepancheg/rust-ide-rust,KokaKiwi/rust,avdi/rust,retep998/rand,pshc/rust,mdinger/rust,barosl/rust,ruud-v-a/rust,pythonesque/rust,omasanori/rust,cllns/rust,jashank/rust,zubron/rust,graydon/rust,pythonesque/rust,aepsil0n/rust,vhbit/rust,nwin/rust